First, you should be worried about not getting hacked, even exchanges who can keep most of their coins in a cold wallet lose rest when they get hacked. Think about a gambling business which has to put as many in the bankroll as possible to provide more coins to whales and when they get hacked.
The other reason is a whale coming in and winning big, which means they may cost the casino a lot or maybe lose a lot but thats a risk.
So, what you as the investor to a gambling ANY gambling business is that, hope they don't get hacked, hope a whale won't bite down the profit. Otherwise house always wins in the long run.
For a gambling site that has been online for over 3 years, i think getting hacked is the least that investors should be thinking.
What they need to worry however is whether they could get thier ROI in a short period of time. but inorder for worries to be lessen just at least invest the very minimum.