Normal AWANA kind of stuff. You want to reward the kids for memorizing scripture or a story from the bible, give them a fake coin or ticket to redeem with a toy, food or in this case, a low denomination piece of currency.
There was no “gambling”, the kids had to earn the prize.
AFAIK, The only place ‘gambling’ is even mentioned in the Bible, is in the New Testament, where the Roman soldiers gambled to see who got Jesus’ robe, and that was to preserve it whole.................