Gamblers play gambling because they want to win real money. If you introduce fake money in gambling and stop the usage of real money, many gamblers will quit gambling because the main motive of these gamblers is to make and earn real money.
Yeah, you can ask kids or under age to play gambling with fake money, but never think that grown up adults will agree to gambling with fake money.
Maybe it would work well for people who accidentally installed a gambling app or they accidentally visited a casino and signed up out of curiosity.
They will not see about using real money because curiosity makes them want to know more about gambling, which is why they still use fake money.
But over time, they realized that gambling games would be more interesting if they used real money.
So the use of counterfeit money can pleasure playing gambling.