What story teller wanted to say?
OP meant that if you are a fearless gambler, your chances of winning are higher as opposed to a person who do not take big risk in gambling. Although I somewhat agree that you should have appositive mode when you play gambling and should have belief in yourself that you will win but again sometimes the luck even do not help the brave too. It will also make you lose big if you take more risky moves.
I smiled as soon as I understood what Op is trying to say. I guess the casino owners are scared/suspicious of brave bettors who take risk with high bet. I thought they want big bets, never knew some are scared of them. Or they are probably terrified of the "bravery" or "believe" lol. Interesting irony.