I also do not believe that traditional currencies will leave our lives, but I think that the cryptocurrency will be able to work with Fiat money on a level. I think I still need some time passed people to take bitcoin as a forum of payment.
bitcoin has not been able to replace paper currency, because it requires several stages and this is very time consuming. so for now bitcoin can only be an alternative currency and is used to trade in large numbers and between countries. need the approval of the world bank and the willingness of user countries to be able to make bitcoin a legitimate payment instrument.