I thought CSAM meant literally “Child sexual abuse material” and that it is a better word than childporn because calling it that makes it sound like its some genre of porn which is too harmless of a description for it. That applies to drawn as well as real depictions. Both are material showing child sexual abuse.
I would say it gives them enough security to test if the payment providers would actually pull through with their threat. Which as far as I know they didn’t try.