I am not totally agree with you dude. Not all of aspect bitcoin win. Let's say about acceptable, think in tjis point fiat win as well, because not many stores or merchant accept bitcoin but fiat is more acceptable if we compared with bitcoin. Many stores accept fiat as payment methods dude.
If you purely look at the currency aspect of fiat and Bitcoin, then it's safe to say that fiat is pretty much unbeatable. Especially when you consider that you can transact offline, where with Bitcoin you always need an internet connection to move value from one place to another. Bitcoin's growth nowadays (for me it has been like this since day one) must come from the store of value and investment aspect. That's where Bitcoin is really shining. And it shows as more traditional investors are finding their way to Bitcoin.
Fiat is the universal currency you can use it anywhere in the world without any fear. But Bitcoin is not like that we can not use it efficiently. Only in few countries, the shoppes are accepting, but in many countries, people don't know what Bitcoin is. So I will also prefer fiat currency is the best way to make any payment. Bitcoin is fast and good, but it's illegal money.