There have been debit cards loaded with crypto for almost a decade now
Your fictional higher standard of currency would say that the euro is not a currency because my transferwise debit card converts it to dollars when I spend in the US
The peer to peer payment mechanism works and all crypto assets inherit that
Well that's not really true, it was headline news when Tesla started accepting crypto payments (and then headline news when they stopped).
Stores accepting crypto still makes the news, it's not common and not something that "just works." But what you can do is at least semi-reliably convert between crypto & things that stores do accept using the various conversions you listed. But you still do have to convert from crypto to a traditional currency to use it as a currency.