As near as I can tell, nobody use crypto for day-to-day transactions because it's deflationary. People do use crypto to buy illicit drugs and guns, pay ransoms, launder money, avoid taxes. Drug cartels settle debts, and oligarchs evade sanctions with it. It looks like particular oligarchs take anonymous crypto as bribes. That's all crime.

Occasionally people speculate using crypto, which isn't technically illegal, but does shade off into unethical. Crypto seems to enable new methods of scams ("rug pulls"), and make older scams easier in the category of "speculation".