Fiat and cryptocurrency are the same but people in society differentiate them and value fiat because its adopted by the government far back, and since the existence of the world and also a specific country, so from my research I find out that government just disliked cryptocurrency for nothing,
So differentiating fiat from bitcoin is valueless because irrespective the importance and massive adoption of fiat currency from its existence before cryptocurrency, it's obvious that fiat is money and bitcoin is money, their functions and contribution in society never depart from each other, so bitcoin now is the shortest way of transactions across the world without much process or procedures, using bitcoin everything buyable is easier to purchase without stress, so from my perspective I prefer bitcoin than fiat currency due to fast transactions process across another country, and nothing fiat can purchase bitcoin can't purchase, so no difference between both because all are currency.
I disagree fiat and bitcoin are not the same, one of the main differences is that fiat is controlled by the governments and there is no limit to its supply while bitcoin is decentralized and has a limit to the number of coins that will exist, while this may not seem like a big deal for those that do not understand how the economy works it is in fact a big deal, governments get a lot of power from their fiat currencies and they see in bitcoin a rival that could take away a great deal of that power and that is why they try to limit its use.