Punishing himself is the losing money aspect. It doesn't matter where it goes technically for it to be a punishment. His goal is to not lose money. But to make

Punishing himself is the losing money aspect. It doesn't matter where it goes technically for it to be a punishment. His goal is to not lose money. But to make it worthwhile (aka the reward part of the punishment), the donations are directed to charity since they need to go somewhere. So that's a small reward built into the punishment.