Well, that's on them. They can do whatever they want and if they are turning themselves to their religion, it is what it should be. And while they gamble, there's no sense that they're in religion because AFAIK, the main reason why someone is in religion is because he wants to change his life.
He wants to remove those vices and any unnecessary thing in his life, so if he gambles and he's going back to the religion, there's no change that's happening on that person.
A person who enters a gambling place will leave his religion at the entrance, there are no religious values in it. Gamblers are easier to accept advice from religious leaders and easier to return to their religion. While people who already believe in and depend on mantras will find it difficult to accept advice from others, dependence on mantras can also harm a person. Spells do not always bring luck to the person, when the spell is read while playing gambling, it cannot guarantee that luck will soon come to him.
Well, you've just spoken about the reality that wherever you are in, spells, mantras or even religion. There's none of them that will guarantee you to be lucky.
It all comes not handy because you'll never know and have no idea when luck is going to come to you. But just whatever you think is increasing your confidence and chance of winning, no one shall stop you in doing any of those.
For me, playing gambling is just entertainment, so there is no need to think about certain spells to get lucky. So just let luck come by itself,
after all like you said there is no spell that can really guarantee our luck. Even if I experience a loss when gambling, it does not become
a burden for me, because from the beginning I was not obsessed with winning when gambling. It's best not to use gambling as a source of income,
so we don't need to think about any spells to win. After all, we all realize that the gambling system is made for gamblers to lose more and benefit
the casino. So why do we spend our time and energy looking for spells or strategies to win gambling.