Today, crypto is a speculative device

Distributed exchanges will solve that quite nicely. When were government workers ever able to keep up with entrepreneurs?

The correct answer is never.

The question is if no country or economy accepts it, where will you spend this said currency? What value will it have?

If nobody accepts it, it will have no value. If that's likely, why are so many people buying it?

Money= durable, fungible, divisible and a store of value. Crypto lacks only the last feature and that will come once it's found its level against fiat.

you just answered my question, a medium of exchange.

It's not there yet, but all things in their proper time. Today, crypto is a speculative device. That was also true of Ohio farmland at one time.