Re:3) If I remember correctly a lot of the "support scammers" also use crypto for laundering. Since getting straight into bank accounts and actually doing transfers often fails - even with the "help" of the victim - another way for them to get their money is having the victim buy gift cards, and then they'll sell on the scammed gift cards (at a loss, of course) for crypto and then cash that out.

You also forget 5) Outright scams, like rugpulls or boiler room-style scams.