Investing in bitcoin casinos's can be good but its also risky due to the fact you have to do it on the right time and it also need to be a trusted party and these are hard to find these days..
I think the whole investment will always be a risk, not just an investment in any casino site. the difference may be a risk in investing in gambling has a high degree of risk. but I can guarantee that this will be much more secure than you play at gambling as a player,
I think most trusted gambling sites, gambling sites is not a ponzi or hyip sites so you do not need to be afraid