I personally still need FIAT money to exchange Bitcoin currency into FIAT, because in my country the government still has not legalized Cryptocurrency. So if I go to the market to buy food, I still use paper money.
That's the real issue. We still need to depend on Fiat money one way or the other. There's no way around it. This is largely because, Banks have dominated our economy for a long time. On the other hand, cryptocurrencies are fairly new to the world with only 10 years of inception. The road for mainstream adoption is still long, since crypto is not fully regulatory-compliant and stable in price yet. For this reason, Fiat money is still the top form of payment among merchants and businesses alike.
Still though, it would be better if we had more choices to spend crypto than simply Fiat money. I believe that if the world would only use crypto instead of Fiat, then our economy would've been fully decentralized. However, this is very unlikely since Banks are heavily backed by governments and they're trusted by many people worldwide. Living only on crypto seems to be a dream nowadays.
Nonetheless, there's a possibility that Banks will adapt to Blockchain technology someday making paper money extremely outdated. Just my thoughts
