Money is still the real reasons why we gamble, been addicted or not, mutual greed or not, all gambling is done to make more money or get some form of reward in the end.
Money is the main reason people gamble even though they don't say it, but always when they start gambling they will think about the money they will win, and people who think gambling is just for fun doesn't mean they don't think about money but what they mean is how they can receive very well every outcome they get, if they win, be grateful and stop, even though there may still be a chance to win bigger, likewise, when you lose, you can accept it and stop without thinking about recovering your losses.
The problem is when the mind is always dominated by the desire to win and cannot accept defeat and tries to recover from defeat so that the situation becomes increasingly bad because it is controlled by greed and refuses to accept the facts that happened that they had lost more money than they could afford.