There will never be one global currency in the world. That involves the elite of each country giving up power. The name of the game is power. Do you think they're going to be, "Oh it's a good idea because then there will be no exchange fees."
Plus wouldn't countries that are doing bad weaken the value for countries that are doing good?
agree with you, despite the actual ego and strength in every country that makes the world unable to have one global currency. EURO is one example of one global European currency, I was very impressed with the cooperation of European countries.
and for global currencies based on 100% internet, I think it is very impossible because the internet is still very vulnerable ... different if the global currency is crypto-based and blockchain, it would be very safe
