Before the existence of bitcoin they're many other digital economic assets that is in line with government policies like crude oil, gold and much more, government where comfortable with this assets trading online, including forex but crypto currency like bitcoin that would have change lives and alienates poverty from the world, government are afraid of its cumulative value.
Bitcoin is an assets that we shouldn't lose or allow to dies off, if you check history of all money weather digital or paper bitcoin circulate faster in values and distributions. As highly respected as dollars not all countries have it but bitcoin is 14 years now, the world is aware of it. Do you think bitcoin will stay if government totally remove their hands or stand against it?
Actually both crypto and fiat face similar problems now. Fiats have become digital, while crypto can be only in digital form. The main compounds for them to function is
1. Stable network of data processing mainframes (mining facilities in crypto and banking networks in fiats)
2. User-friendly interface (wallets for crypto and online banking services for fiats)
3. Support (branches and ATMs in fiat and support teams in crypto)
4. Privacy (multiple cryptography and decentralisation technologies)
So all the problems come from these things, and both fiat and crypto are continuously dealing with them.