If they’re paying out ”bait gains”, aren’t these just ponzis like Bernie Madoff?

They usually dont pay out anything. It's just target's "investment account" value grows until they want to withdraw. Obviously some scammers can even pay something at first, but it's just not usual strategy.

In the article it says some victims were allowed to withdraw small amounts, and one says he got it as a gift card. So that's where all those gift cards from the email scams go...