It is very clear and it is usually an entertainment for the rich people. They show their entourage or their business partners to show how much money they got when they bet on a game like poker. But for poor people, gambling was never an entertainment because the rush to win is already right from the start because they hunger for a lot of money.
You are right. Wealthy people don't care about money too much thus they can focus on the entertaining part of game. Just as poor people can't be happy enough at any activity due to lacking enough money for life.
For poor people, actually play gambling to get instant money is something wrong to do. Because it is better for them to do more important thing else than do gambling because it's risk is high and can take all their money.
This is because they normally do not have access to funds and try to gamble with their limited money to make more money with it but end up loosing that as well because they do not have prior experience as either. This is the reason why gambling is banned in many states. The state does not want its people to loose miserably in gambling and hence suffer.