Yes, crypto's main use is crime. Its supporters have various arguments for why crime is actually good.
For comparison, to use a bank card you first need to provide all your details to bank which can share them with anyone they want, and then your application can be rejected for arbitrary reasons. And after this again the bank can share information about anything you bought with the card. There is even an official organization for sharing data about consumers loan history and this is totally not a crime in our weird society.
It is quite a very poor use with such "crime" happening all on a public and transparent blockchain, making it very easy to trace all of that (even if they use a tumbler / mixer) with the funds certainly seized and frozen as soon as it hits the exchange.
In fact criminals and scammers still use banks and Zelle to facilitate their criminal enterprise - [0] [1] in the trillions of dollars.
[0] https://www.buzzfeednews.com/article/jasonleopold/fincen-fil...
[1] https://www.nytimes.com/2022/03/06/business/payments-fraud-z...
Once again, Bitcoin is worse for scammers, criminals and ransomware than using Zelle and the banks for fraud.
You should be asking why the banks continue to move trillions of dollars of illicit funds for criminals for years without them doing anything. Same with Zelle.
The law however arbitrary and flawed is the source of morals for most adults.
George Carlin said it best with “Think of how stupid the average person is, and realize half of them are stupider than that.”
"First they came for the socialists, and I did not speak out— Because I was not a socialist."
Crypto's main use is crime insofar as its main use is denying monopolistic/governmental control, and anything that the government bans is a crime.