There are quite a few differences between bitcoin and fiat but some of them are: the possibility of sending any amount of money for a very small fee all over the world, this is a great advantage over fiat, the pseudonymous nature of bitcoin offers privacy from the eyes of banks and governments, bitcoin can be used to carry great amounts of money on you without anyone knowing about it including banks and governments, the same cannot be said about credit cards and having a lot of fiat or gold with you is suspicious for some authorities.