The main issue with crypto is the exchange rate and volatility. The local ATM gives you a shitty rate on bitcoin and by the time you spend it its value may be lower or higher by a big margin. The merchant may experience a similar issue.
There are some ways how you can solve this. You can convert to and from stablecoins. You can use hedging and use cfd or futures to keep your bitcoin on stable fiat value. Depending on what you need, this can be done on exchange, with some payment gateway or even trustlessly via smart contracts.
So, I use fiat to buy bitcoin, convert it to a stablecoin, go buy lunch, convert it back to bitcoin, then the merchant converts it back to fiat. Why jump through all those hoops to buy lunch? or anything for that matter. At this point i could just use gold.
I'm talking about the reality and in the real world the solution you propose does not exist. For some reasons stablecoins do not seem to be used outside few online exchangers.I can't find them available at the local atm.
