Yeah, it's all about profit. I tried different ones and got a reasonable profit because I bought at the right time (Together with some small boost to reputation). But that works only for people who understand where the market is about to go.

The fact that most of them give less than you pay is a super scam! And still, people buy - that I don't understand. They don't get anything in return (Only reputation).

Probably there will be some super changes in the future.