Very risky, some guy could come along and clean house. From what I have seen and experienced they have been profitable all around. In my opinion just-dice which is done in CLAM currency is pretty good for investing in the bank roll.
Just watch out for that risk though.
I'm sorry but it seems like you don't know much about how casinos operate, typically they are protected agains "some guys who come along and clean the house" by imposing a limit on maximum allowed win per one bet. Usually it's on 0.5-1% of the bankroll size, so it's very unlikely that they house will ruin or even take any significant loss, worst case that I've witnessed with my investment was 3% loss in a short term, but it recovered in lass than a week.
And thats we should really to think about investing on this gambling houses. Profits arent still assured or guaranteed anytime because there are really times that the house itself would have negative profits which means those all investors would gain nothing on that period also but still its a lot away better than playing gambling on the site itself.