Things like that actually have no effect on gambling, I used to have sacred items before gambling, I believe that when I carry those items, I will be lucky. But when I gamble, instead of winning, I lose. After I saw several articles related to it, I realized that all these things are suggestions that make our self-confidence increase.
I agree with you, but there are many people who use them. Let's take sportsmen who cross themselves or make other gestures before they start. I, like you, am more rational and don't believe that anything you say or do will have an influence on the outcome, and if it turns out that by saying something or making a gesture you win the jackpot it's purely by coincidence.
If the sportsman I know before starting pray to God first, while gambling, is it possible to pray to God to win gambling???
maybe if the spell is only to increase confidence when gambling but involving God in gambling I don't think it's worth it.