Originally Posted by
milypan
I'm guessing it's under MS because it's a way to pay bills by card that normally wouldn't be card-payable. But nobody ever claimed that it you could "scale making money" with the service to unlimited levels (and, for 99+% of the cards out there, you won't make any money at all, other than hitting sign-up bonuses, because the rewards aren't worth the 2.5% fee).
If there were a way to make unlimited amounts of money using this service or any other, someone would have already arbitraged that away.
It's partly under MS because there
used to be a "loophole" which made Plastiq earn 3x with some cards. (And 3x may override a 2.5% fee enough, depending on how much you value the points you're earning at 3x.) But that appears to have ended recently for the most part.