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.
I also believe the same mate,that cryptocurrency will never make Physical money gone
Maybe in future the main currency to be use is crypto because this is designed for computer generation as virtual money but we all know that this needs internet and electricity to function while fiat can operate on othr side so in this they will both beneficial for the world when the mas adaptation of cryptocurrencies happen soon