Not everyone can spend fiat immediately. I can't. While I do everything I can to barter and get others to pay my rent, I only managed that about 1/2 the months last year, and my landlady doesn't take plastic, Hive, or BTC. She'd take a check, but I'm not setting up a bank account just for her. I'd still have to have cash in it to float checks.
Nice thing about crypto is it seems to be readily sold for cash when you need cash. I have to say that I can only assume that is true, because I've never ever. Ever. I'm not against crypto as money. I just already have enough nontrustworthy banks and etc. to deal with, and see no good reason to add centralized exchanges.
If there were dexes that ignored KYC I could use without a bank, I'd make some effort. From time to time I am told there are, and I have a look, but there really aren't, and some detail or another means my deets would be attached to my ability to exchange currencies, so I don't. I do wish there were, because I would. In the meantime, cash transactions are anonymous, and that's what I do if I can't wangle someone else to pay my obligations.