That's called good bankroll management.
Their max win amount to bankroll size ratio appears to be the lowest among all the casinos in the review. This doesn't allow both significant drawdowns in the bankroll and massive losses by the gamblers, so we might not expect whales losing thousands of bitcoins at a time as it happened with BetKing. But this strategy seems to be working in the long term, and it is working perfect at that!
But now it doesn't look good bankroll management because past earning records will not give any guaranty of same earnings in future as well. So now left with only two sites and if big whale wins in crypto-games then his investment may down a lot and all his profit may be eaten up very fast. Now again need to find another one or two sites investor need to add back any of the old sites.