I like it when a site adds some gamification elements to reward regular play. I saw on https://wildrobin-canada.com/ that they have a shop where you can exchange coins for bonuses. You earn these coins by playing games and completing achievements. It is a nice way to get some value back even if you are having a bad run on the slots. It feels more engaging than a simple comp point system where you just get cash. Just do not let the achievements drive your betting behavior too much.