As another user so eloquently put it, hilariously overpriced in-app purchases. And now you can't even pin the app to run on background, which is why the app must be turned off a lot and the devs will be losing in ad revenue. It's like they don't want to make any profit on this at all. Edit: now when i watch ads, they don't close and I don't receive rewards. Rebooting phone and clearing cache didn't help