I would rather advice to invest in 1 casino and use your other funds to invest in something else. An altcoin, stocks ore even a start up. Don't diversify just your money into a sector like gambling, also diversify in investment methods. This way it's really diversified.
The problem with crypto investments is that it is hard to find real investing opportunity in the sea of scams.
If you want simple investment then your choice is limited - you either will invest in casino bankroll, maybe some lending site, and then what?
You can try find good ICOs but risk of this investment is significantly higher. I am not even talking about cloud mining because every new CM is pure scam.
So investing in reputable casinos are somewhat easy way to achieve small profits without big risk.