Guys, I don't get it. If you are saying "Once a reasonable profit is made, you have to pay our share and withdraw your balance" why don't you play by yourself and have all the profit not just a share? Also you say on your site that the minimum investment is 0.1 Bitcoin which is a big money and and I can't see why would people invest such amount on an unknown site.
Because they know they will not really win every game they play. Because this is gambling. Experience doesn't give them any edge. In the event they lose all your money they don't have liability. They will just say, "sorry boss, we lost your bankroll better luck next time" then just go about their lives and tries to trick another fool. I don't believe them.
If they really are good gamblers, then post a live video of themselves gambling at some online casino where we can watch the video and at the same time look at their bets in the casino. Let's see if they do well and get a profit.