Obviously them can never be the same but the similarities is there, because we use fiat currency to purchase pizza and we also use cryptocurrency to purchase pizza, which is documented in forum that somebody purchased pizza with crypto when Bitcoin did not dominate like as it's currently, so since this analysis happened previously, so while can't us accept the fact that btc and fiat are correlated the only difference is the regulations.
It's not just about the rules. It also lies in the principles of operation and areas of application. Under the current systems of public administration, which operate in all parts of the world, fiat currencies act as the basis on which the functioning of the economic system of any state is built, and not just payment for goods and services, and there is no escape from this.
Ok, now I comprehend your area's of concentration but from your comments here, I'm putting it generally while we think cryptocurrency is differ from fiat currency, except it's regulation which involves decentralization and centralisation, looking towards it critically it's clear that they have the same functions.