crypto currencies rule over currency market and local currencies get disappear slowly in a decade or two?
This thing you had said would really be an impossible thing to happen. Cryptocurrencies might be highly adopted but it would just still remain as an alternative and wont really come to a point on where it would become the main trend. Government wont allow such thing and not all people will switch on a thing that hasn't being backed up by something.
It might happen dude. In china, particularly in Shenzhen, they dont use paper money anymore or atleast its minimal. The only problem I think with that scheme is that they're security is compromised and their government can tracks what they buy and do. I believe that these kind of problem would be solved by blockchain technology wherein they dont need to register their information.
