I wonder if people would still be excited about a game that maybe you could earn 30% in a whole year on your btc, but in order to do that, you had to keep logging in to collect. Add pretty graphics and noises, and it might be fun. Sort of like cloud mining, but real, and a game that you could lose your income. Maybe even having prizes to give out from uncollected earnings.
Why hasn't anyone done this?
Because where would the 30% come from?
Suppose I open the site. You deposit 100 BTC, log in every day, hear some beeps, then a year later I have to give you 130 BTC? Why would I run such a site? Sounds to me like I had to pay for hosting for a year AND give you 30 BTC of mine. Lose/lose.
Maybe a few people would deposit small amounts and forget to log in and so I could use their small amounts to pay you with, but anyone depositing a big amount would likely not forget to do whatever they needed to to qualify for the payout.