​Why doesn’t someone create a gym that pays you to go workout?

I know it sounds crazy, but hear me out. What if there was a gym which charged say $100/month for the membership, but for every day someone actually goes and completes a whole workout there (can be based on some pre-determined amount of time, like 30 min or so), the gym pays you $3 back.

This would incentivize people to actually go to the gym more often, and a lot of people would probably sign up since it seems like such a good deal and you could potentially be paying less than $10 a month for a membership if you go every day.

I’ve never seen any gyms that work like this, is there any reason why this wouldn’t work?