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 don't believe Fiat and cryptocurrency are the same. Yes, they might be performing the same functions and today there might be some form of transactions where crypto is been accepted as a means of payment but that is some individual organization or businesses which doesn't stand as a total representation of the Country. You must also understand the difference in value fluctuation or the volatility in cryptocurrency price which is not the same as fiat. Hodling your crypto at any given time even the same amount but you realize the monetary value fluctuates which makes it difficult to have a steady value except for stable coins which is almost stable because even that, you still notice a fractional variation in price.