I think fiat and cryptocurencies have more in common than we generally assume because they both rely exclusively on trust and the law of offer and demand. That said fiat are also indirectly backed by networks of banks and central banks and many other institutions yes. What I like the most in crypto is the transparency of the rules (codes) and the endless possibilities in the real of smart economies and digital scapes.
Sure, traditional and digital money will be always connected. I do not understand why fiat should fail. Yes, the cryptocurrencies will be used more often in future but it will not change much.
Crypto will be part of our future and i want to study and learn about it while it's not yet popular just in case we can use it for the future so i don't feel ignorant if crypto will be accepted in many countries.