Ember does have some gambling options, which I only use to the extent I absolutely am required to, as they don't let you cash out some of the cash back rewards for things like the "airdrops" you get for buying their platform tokens, without "playing through" the sats. But yea, some of the in app rewards are pretty nuts -- I bought over 19,000 sats the other day for $2.97 worth of in game diamonds (and in turn this I often subsidize a bit with Google opinion rewards...). Can't say I totally understand how they're able to swing such things but I suspect they catch enough either on the advertising side, gambling side, or both to generate enough revenue to pay out. It's definitely an app that requires some conscious discipline with and will make you jump through hoops, but it keeps my zaps funded anyway.