Exactly  .   we are now on a modern world , that is why we also need to go with the flow .   bitcoin or cryptocurrency in general is the most suitable payment system to be used  on it because cryptos are the most advance so far between other's out there  but we arent also forced to used them because there is no rules so far that restricts the use of local currencries  .

Fiats on the other hand wont ever be vanished because they are still the most legal payment system even if we say that we are now on the future .