Still sketchy at this moment. Cryptos are still now widely accepted to majority of countries. Although it is neutral, meaning not illegal, the support is not there. Cryptos are still facing issues in the eyes of the governments so maybe there will be decades before this scenario happen. At this moment, I do see it more for both cryptos and fiat to coexist and not mainly cryptos alone. But who knows, since the development regarding technology is becoming faster, cryptos has a huge spotlight among other digital currencies.
It is possible that someday all country accept Crypto Currency and it will become Universal Money?
Because I am a positive thinker I think its highly possible, because cryptocurrency is a high technology-based digital asset or currency and because our time now is too much relying on technological help it would be easy for the general population to use it as the established technology base asset or money if that time will arrive I'm sure that using cryptocurrency for everything we need will be as easy as counting.
The problem it would encounter in my opinion is the existence of other digital currencies. There are many fiat based digital currencies which are supported by many countries. Ofcourse, in our point of view cryptos has advantages so let us hope others would also appreciate this technology.