Gambling has never been and never will be good. Simple thing: Someone has to lose to someone else could win. You will win once, but then you lose a lot more. Ordinary mathematics .. nothing more ..
Well, that is for the players but we are talking here about investing in a gambling sites and we are not subject to your computation. It is also a simple math that since gamblers loses the house wins most of the time, the only problem now is how to choose a gambling sites that are trustworthy.