It would be great to see cryptos replacing fiat money. I know some people do not want to see that happen but it is an option. Nowadays, it is very hard to use cryptos in daily routines. It is hard because of the exchange rates and places to do it. It can be done online and it means you need a good connection. The world is still dominated by banks and they do not allow cryptos. Some countries do not allow their citizens to use cryptos as well. In that case, it is very hard to use cryptos in daily routines. I believe this will happen one day but not now.
That's the most basic use of it, as a replacement for paper money or plastics that most people commonly use today for paying services and good. However, I think that most people after the market boomed in the past several years, are using their cryptocurrency holdings for investment purposes or for long time holdings, which is more profitable and gainful rather than just using it in the it as a currency. I would say that they are very useful because they give you the capability to actually gain something in return to help you with your expenses.