If you want to invest on casinos, pick one with a good bankroll management (for example, crypto-games) because there are times that a high roller would win x consecutive times and you will surely lose your investment in no time.
There are several problems which maybe you are not aware of mate and hence let me help you out. The first and actually the biggest danger is that the site we invest might turn scam anytime.
Secondly, there is only a house edge of 1-2% and chances are there gambler wins too. Thirdly and might be wrong, I wonder what stops site from claiming their own wins as players, I mean they pretend to be players and since they know the seed win the bets ?
And aside from that, even we can that investing in a casino's bankroll looks promising and profitable, why only few users here in the community likes the idea of investing on a gambling site's bankroll?
See? Because that is really not profitable. When I say not profitable it doesn't mean you will lose. What I meant here was, the profit you will made on a long run is not worth it so in other words just a waste of time although good thing is passive. Just bet on the gambling site that it will not run while you have an active investment there.
Scamming people for their bankroll or even running a negative bankroll for a while will result in people withdrawing their funds and the bankroll being pointless (0).
If the casino doesn't have their own funds, it's in their best interest to run the bankroll as efficiently as possible.