investing in gambling : you'll get divident from your initial investment in gambling site, since gambling site has house edge, it will make sure they make profit in long time. but in rare occasion, they can bankrupt too (in example justdice case) if someone trick them or someone iis very lucky to defeat house many times
The more important risk to worry about is the trustworthiness of the person running the gambling site. You do not want him disappearing with your money.
