I think it will not affect him too much because you are aware of this and you are aware of this. You are looking for ways to keep him away from games or you have convinced him that it is a game for adults. Gambling games should never be played in the presence of children. I hope this title will raise awareness for all gamblers.
And why i said I see no big deal in this is that, like you said, children can not differentiate good from bad, same way they can not differentiate a gambling game from a normal video game which alot of our children play this days.
If you are gambling, like playing a slot game, there is no way your child will know that you are gambling except you tell him or her, what he or she will understand is that you are playing a game, simple.
And if you want, you can one day download a video game from Google playstore or iPhone app store and give the child to play, and make him or her understand that that was the same game he or she watched you play the other day, this way, they won't ever know anything about gambling until they grow up and start mingling with people outside like in school or so, who they may learn such thing if people they mingle with are people who already know about gambling.
That's actually a good point, where you just simply tell your children that it is just a simple game, but I still believed that they would still be learning that the mechanics of some games would need some bet if you do not inform them about the bad effects of gambling which they might think is normal cause they can't distinguish what's wrong and what's right. I think it's not really a good idea to bring your kids into an environment where people are betting up their money and relying on luck to win, it is not just about the game, it is that we are trying for them to not adapt and learn this kind of habits cause not only that they are a good imitator but also environment influence their behavior. When the time comes they encounter a gambling game that is familiar to them, for they are gonna be interested in playing it and it will continue which might lead to addiction. It's really much better for them to understand and learn when they can already decide for their own.