I can believe in fiat at this time but in the future I can not because we are using smart devices in the digital world and we can use payment tools online such as bitcoin, altcoins for it. I feel easier ans faster than fiat. it does not need much private information or verification on payment and It's easy to transfer money to another one .
Partly you are right but I think there always will be existing countries were digital payments are simply not possible, I must say that I still believe in Fiat if I think about such situations.