I was born in a secular family. I have never felt any religious pressure in my life. In my opinion, people can gamble without harming others or themselves. Religions have made rules like this in the past to prevent people from harming themselves and others. In my opinion, religions are a law book for their time. But in today's world, we have our laws. That's why gambling is legal in most parts of the world. If you don't harm yourself or anyone else when you gamble, I don't think God is bothered about it.
What we have seen so far is that gamblers are doing more harm to themselves rather good. The reason why most of religion put a ban on gambling is because it mostly bring loss to gamblers. Religions are old but there laws about gambling are still valid for current era IMHO. Rules are rules and they must be followed to avoid any damage. See results of gambling, we don't find many who have got benefit from gambling.
To be fair, there have been indeed people who have gotten benefits from gambling, specially those who have managed to hit the jackpot and retire from gambling afterwards. Though, because of the nature of the game, those cases are supposed to be rare, it is a reality gamblers will (in the majority of the cases) to lose money to the casino.
Though, I believe those Religious restrictions on gambling and betting do not have much to do with the benefit or the lack of benefit which gamblers can get out of it.
If I had to guess on the reason most religions discourage gambling, then I would say it is about how greed is very frown upon in most of them and gambling is one of the most greed-inducing hobbies/activities one could partake in.
Also, keep in mind in most of religions it is also forbidden for people to ask for interest on their loans to others of their community (usury). In our modern era we take for granted we can ask for interest to people who borrow money from us, but in the past it would have been considered to be a serious sin. It is about the same with gambling.
Both interests and gambling used to be perceived as a way to hurts members of the community, instead of a legitimate business model.