In general, all this makes me very suspicious of the honesty of these investment projects.
Investing in the crypto gambling site is too risky because we never know how high the coins will increase.
You seem to be right, it may be the reason why some big casinos like Stake are not offering these kind of investments... Maybe they think it's too risky for the investors and they don't want to be seen as bad actors. 
If the investment is received honestly, then it makes no difference how much the coin grows. 1 bitcoin is always one bitcoin. But if the owners of the project are not honest, then this really starts to matter - greed will not allow them to return the coins that have risen in price.
And as I see, project owners have different strategies for "squeezing" investments - firstly, how to check the whale was lucky or the casino owner himself "won" from the investors?
Secondly, read how snipie lost a significant share of his profits (this can be seen on about 19 page).