A currency has to be accepted in order to perform its role.
Good luck buying groceries or paying the mortgage with Crypto.
Which is why I have a couple bank accounts. If these banks decide they don’t want to work with me anymore (happened a couple times already), or if they decide they don’t want to send money to, say, a particular country (hint hint), I’ll have crypto as a last resort.
(You conveniently left out “cash” from your reply. Cash. I’ll buy groceries with cash, if I can’t use my card.)
There are some stores that do accept BTC, but it is not widespread. It is mostly coffee shops though, not grocery stores.
And it varies from country to country. (In any case, I wouldn’t use BTC for everyday purchases – it’s too volatile, and transfers are too expensive. As long as we’re stuck with fiat-based economy, stablecoins are the way to go, IMO.)
there is invariably a vantage point at which non-fiat payments are accepted. this may be crypto, given that there is still infrastructure available for it to operate, but that's unlikely imo.