I agree with you, because we are equally in need, we need fiat money because we know that not everyone in the world can access the Internet or use the Internet.
Thats true actualy i have found some people who realy dont know how to use even an old mobile phone as a basic call and text communacations only. In that case they need fiat money because they dont know how to use internet but at the same time they can also slowly study about on how to use crypto currency.
It's not the problem of cryptocurrencies. The problem is that people. If they have to use cryptocurrencies, they will learn how to use it. Remember when debit cards were created recently. Now all the people use them. Becasue they have to use it.
I do not ignore bitcoin problems. But I think cryptocurrencies have the potential to replace fiat money in future. However we need both of them now because of some problems.