And yeah, as WhiteElk said, that third party client, which is really popular- the reason I don't use their service for many games is due to what he said. I know with Impulse, if they jack things up bad enough, and I have to dispute, my games aren't going bye-bye. BTW, I'm not saying chargeback is the immediate option, that's an abuse of power- but if I really got hosed by someone, and it couldn't be resolved in a timely manner, I would.
With that other client, if you got enough games from them they got you by the balls. I am willing to get games on that client, but only with retail sales (which makes that client just an annoying DRM scheme), or games where you're just buying a serial you can take outside of that client (such as Mount and Blade games).
At least for me, return policies and consumer protection does affect sales.