They don't even fiat too,they can survive their life just how the people did on stone ages.
We do need fiat. It's convenient and with chargebacks people enjoy a wide level of confidence in their finances as a whole. It's what I consider a system that works extremely well, especially within well developed countries.
Crypto on the other hand sucks hard as money. The user interface sucks, the user experience sucks, you enjoy no buyers protection, insurance, there is volatility, forks, and the list goes on.
I won't say it's one of the worst forms of currencies at this stage, but it's definitely close to that. Fiat is superior in almost every way. There is no point in hyping up crypto as currencies, they suck hard in that field
There is one way in which it is not superior
As even fiat currencies in most developed countries tend to depreciate over time. Some less, some more, but it is still a one-way street for all of them without exception (something like "all paper will burn"). Bitcoin is different in this regard and while it may be as volatile as fuck, it is not like it is only losing value all the time
Indeed, it doesn't make a lot of difference if you have to spend all your current earnings on your daily paychecks. But if you don't, then it does. And in that case you will be more particular about strengths as well as weaknesses of fiat currencies, and things may start to look a little bit different to you