Earlier quoted context omitted.
As much as they need for what? Aside of ransom payments and drugs, you don't need to buy cryptocurrency, ordinary fiat money works just fine as a medium of transfer.
I pay for vpn with crypto, the provider doesnt even have my email. How do you do that with ordinary fiat money?
By sending an envelope with cash. Services often offer that option. No E-mail or name disclosure required.
A few advantages: Your payment isn't traceable for all eternity for the whole world to see. The amount I pay isn't suddenly worth 10% more or less the next day. Better for the environment.