I agree with you, setting limits is one of the keys to smart gambling. gambling excessively is the same as leading yourself to ruin. Now, even though their religion prohibits gambling, there are still people who do it secretly. especially with the current existence of online gambling which makes it easy for all gamblers to gamble anywhere.
If you play with clear limits, it will help you not to play excessively because whatever religion teaches is usually excessive things will never be good in the end
Additionally, over reliance to luck is bad. There is only one God and you should only believe and rely on Him. Yet in your mind and you may not notice it but you are creating a false God that you want to do something specific for you. "please make me win this time, if you make me this I will ...". Such religions doesn't want that.
If you want to create luck, you create it by handwork and not by preaching false god that you've just made upon on your mind. Most misunderstood this but this is the reality. If you want to be successful in any field, back it with handwork and believe on something who overcome the world. You build the life you want by consistent effort and not relying for luck. If doing so, bad luck is the one that may come to you and you don't want that.