The moment all the countries convert to crytocurrency would be the beginning of many amazing things to happen to the world and the financial sector, the process sending and receiving funds worldwide would become very fast and easy, it would lead to growth of businesses and make life easier for citizens of the world.
Cryptocurrency have the advantages in the part of trading industry, which have a less fee, anonymous and can be used worldwide. Do we really need to transact worldwide when there's a good economy in our country? If all the countries convert to crypto, i think the crypto can control everything and we would not like that. We are people created by God, we are the most intelligent creations , so think before you agree.