but gambling, even tho is prohibited, is often what entertains most prisoners. there is no actual money in prison so they often exchange in other forms of currencies like food or smuggled items. even their way of gambling is smuggled. cards, dice and even information from the outside are all smuggled.
No adult in the prison will gamble with his food. Money is used to gamble in prison. If cards and dice are smuggled into the price. Money can also be smuggled into the prison.
the reason why gambling is prohibited tho is because it might escalate into fights if someone for example loses and doesn't pay their debts
In addition, I believe that the prisoners are not working, which means that they don't have any income. That's why gambling is not allowed because the government believes that prisoners wouldn't have money to gamble.