The system works in favor of players who like to play and wager for some time.
If your player comes in, deposits 1000, bets it all on red in roulette and loses all, you don’t make much.
If your player comes in and deposits 50 and plays slots for an hour, you do well.
It has nothing to do with deposits and everything with how much time is spent wagering.
It’s just like your reward points in Vegas.