Fiat currency is what we need to maintain the global economic system. From my point of view, even cryptocurrency has a lot of advantages, it still can not become an official currency and we also can not eliminate fiat currency.
We can do this because it is a currency only but crypto currency is an investment as use to invest it for our better financial crises. We can reduce the number of crises and we can get better earning resources we should try to use crypto currency the most as it gives us profit as well saves our future we can do anything with crypto what we can do fiat, so the future of fiat is not so good according to me.