Children are forbidden to gamble and it's very sacrilegious to engage in gambling activities around them because of the disastrous effects it does have on them. Gambling is strictly for adults about 18+ because it's psychologically believed that they can make financial decisions for themselves as well as control what's not good unlike children who will engage in whatever they see an adult practicing around them without knowing the effects or how to control their engagements in these activities
At the very tender age what children do mostly is copy what they see around them and since it's done by someone believed to be older than them, the naturally interprete it to be okay because if it wasn't then the adult will not be engaging in such and this has been one of the reasons adults are strongly advised to not engage in gambling in the presence of these kids so they don't copy it by default and for them addiction is as quick as when they just started, they get addicted almost immediately and grow with it such that it becomes part of them.