You'd do it with your smart phone. Have a vendor with w pub key as a qr code and you'd have someone scan it and then they authorize the app to send to it. I think the major exchanges have these sorts of things already.

The problem is verification is slow.

Ignoring the fact that crypto is highly violate and not at all usable as an actual medium of exchange for everyday goods because of that fact... Crypto transactions are just really slow. When you go to a store and use your credit card or debit card, those transactions are real-time, and were verified by some mainframe that's sole job is to process hundreds of thousands of transactions per second, from hundreds of thousands of banks and individual retailers, all while also providing suspicious transaction monitoring in that 3-5 second timeframe it takes for the card reader to say "Approved".

Blockchain transactions can take literal hours to verify, which for a vendor, you can understand would be completely unworkable. That's not to mention with cryptocurrencies like Ethereum, there are additional fees to merely have transactions be processed, which for low amount transactions could be equal to the initial purchase price itself. Suddenly a $1.29 pack of gum actually costs you $2 because of network fees -- scaled across any number of daily transactions...

These issues are why there are crypto exchanges -- cryptocurrency as a decentralized blockchain with third-party verification makes it incredibly useless in reality -- crypto exchanges act as a third-party with liquidity to side-step blockchain verification and instantly deposit the amount transacted into the wallet of other exchange members. And, naturally, on top of whatever transaction fees the cryptocurrency itself might impose, there are then also fees that the exchanges impose for their their services. Which, if you put any thought into for more than a few seconds, you will realize completely negates any of the supposed virtues of cryptocurrencies; Chain of trust? Nope, you're transacting between ephemeral virtual wallets. Decentralized ownership? Nope, all your funds exist with the pseudo-bank that is the exchange -- you do not control your wallet. Insulation from market volatility vis-a-vis the '08 financial crisis? Obviously, laughably not, crypto is extremely volatile and value is more or less directly tied to stock market performance.

If you want to use crypto for day-to-day usage, there are a million disincentives, and many more reasons to just use a debit card or credit card. To my knowledge, the only places that have seen any modicum of crypto uptake for daily usage, are countries that have such unstable currencies that the volatility of crypto isn't as bad in comparison; Argentina comes to mind as one such country. But... In those same countries, there's much more incentive to just have your savings in a foreign currency, such as dollars or euros, which are stable; having an interest rate of 0.5%, the currency having 3% inflation, is dramatically preferable to >=10% yearly inflation. In countries such as Argentia, again, Turkey, and Russia it's much more common for people to have a bank account and store their savings in dollars to avoid the volatility of their home country's currency instead.

At the end of the day, these barriers are more less why the only uses for crypto currency are as 1. A speculative asset, 2. Illegal goods, 3. High inflation countries, 4. Legitimate transactions

Now, all of that being said, let's just ignore for a moment all of those issues. If crypto were to see widespread adoption, crypto exchanges would have to take a heavy interest in physical, card-based transactions with point of service terminal integration, which would mean working with PoS terminal providers like NCR and also working directly with financial institutions in standardizing crypto cards the same way financial institutions standardized chip readers and NFC tap-to-pay. To be blunt, neither financial institutions nor crypto exchanges have any interest in working together at that sort of integration, nor do financial institutions trust working Kraken or Coinbase or any of the other dozen exchanges -- none of them are big enough to have the sort of influence and reputation that would warrant any close ties. There's also the issue of government regulation, which needless to say is heavily influenced by financial institution lobbying. Coinbase in particular has tried to establish itself as a reputable exchange, but has seen legal scrutiny from the both the Securities and Exchange Commission, and the Federal Trade Commission, both of which take a dim view towards cryptocurrnecy as a speculative asset, and not an actual currency. Now, that could change with the current administration who has positioned itself as potentially being more crypto-friendly, but I wouldn't discount the institutional momentum against crypto. This legal uncertainty is yet another pain point which makes practical daily usage very challenging.

In a word: crypto fails to deliver on its initial core aspirations, is seen as disreputable by financial institutions, crypto exchanges regularly have legal challenges against them, and no exchange has the reputation for broader physical adoption due to the lack of centralization.

I'm stupid, so for other stupid people like me:
https://en.wikipedia.org/wiki/Point_of_sale

>>2324
I forgot to mention one last big issue. I touched on it by describing cryptocurrencies volatility, but forgot to go into more detail. That being: convertibility. I think this comes as something of an oversight when discussing cryptocurrency, given it's nature, but when it comes to currencies and the acceptance of foreign currency for international exchanges there is ZERO question that you can reliably use a credit or debit card in any country or when making online purchases. Occasionally there are fees imposed, particularly with in-person transactions, or with ATM foreign currency exchanges, but often international purchases have no additional fees. Again, this may come as something of an oversight, but when it comes to the ability to use an ATM, even in other countries, it's a mostly painless process to get local physical currency. ATMs are extremely numerous, and especially at international travel destinations, and airports, physical foreign currency exchanges are also very common.

This comes in contrast to cryptocurrencies because the medium is the asset. Whether it's converting between USD and CNY, or CAD and JPY, or EUR and SEK, or CHF to WON, etc. there's very little volatility in exchanges rates because on-balance, currency exchange rates are determined by international trade expenditures and revenue, foreign currency reserves, and above-all exchange rate to the US Dollar as the world reserve currency. Generally speaking, the biggest source of volatility in exchange rates tends to be as a result of domestic inflation; ergo, if your country's currency has inflation, your currency will be weaker in relation to other currencies, and thus the price of foreign goods will become more expensive, however, if you have an export-oriented economy this devaluation can make the price of domestic goods artificially cheaper for foreign buyers. So, to give an example, if Brazil has high inflation, importing foreign goods may become more expensive, but for other countries the price of agricultural products out of Brazil, such as soy beans, will decrease relative to their previous price. In the long run, these trends are generally self-stabilizing absent dramatic economic intervention by governments so that prices and exchange rates remain relatively stable. This is largely why Neoliberal economists advocate for free trade and the elimination of trade barriers, such as tariffs, because they otherwise distort international markets.

With regards to cryptocurrencies, however... None of that institutional backing exists. The price of bitcoin, therefore, is not determined by the usage of bitcoin as a currency, but instead, bitcoin's convertibility into other currencies and as a speculative asset. In this very basic respect, all cryptocurrencies fail to meet the basic requirement of a currency, which is to be a stable medium of exchange.

If tomorrow, the United States and China agreed to denominate trade in terms of bitcoin, however, we would generally expect the price of bitcoin to stabilize, but such a thing is impossible to imagine. When countries do trade at the scale that they do, they generally are buying USD to make purchases, often with gold. If you're familiar with the fact that the Federal Reserve Bank of New York has a gold vault beneath it, this is what it does all day: people move quantities of gold between accounts (countries) to settle currency exchanges. There's no reason to expect we would move from this system because gold is a physical asset that has been used for hundreds, thousands of years for essentially this sole purpose. Bitcoin or Ethereum provide no real benefit compared to how international trade already occurs.

Now, this isn't to say that it makes sense to have a purely gold-backed currency. Gold, being a physical asset, has the very real issue that it stifles inflation, which is bad for the expansion of a national economy because it constrains the money supply. If you're familiar with William Jennings Bryan, and his Cross of Gold speech, this was precisely the issue he was campaigning on, and hence why he wanted the United States to adopt silver as an additional metal for which to base the national currency on, as the greater supply of silver in relation to gold would provide more room for the national economy to expand the money supply by increasing silver reserves. This is no longer how currencies derive their value, however, and instead they are "free floating", not based on any physical asset, and their price is determined in relation to trade volume exchange, as previously described.