I believe that gambling should primarily bring pleasure to the gambler. Of course, the financial component is not the least important, but since gambling is a high-risk entertainment, you should always be prepared to lose your money. At least over time, the gambler begins to get used to the fact that losing is as natural as winning, but at first it has a very strong impact on the psyche. So yes, gambling affects the mental state of a person, especially if he has a heightened emotionality.
Yes, it should, but that's not what every gambler thinks about it. Most gamblers take gambling as a way to get money and that is what they want from it. They don't care about pleasure, they don't get any pleasure in gambling because all they want is they keep winning which is technically not possible in gambling because it's a game of luck and one cannot always be lucky. Even if someone keeps winning for a few days, they will eventually have to lose to the house.
And, those who manage to win something good initially in gambling, tend to have the mindset that they can win at least something on top of their bankroll every time, and sometimes people do win something every time but what makes them deprived of those winnings is their greed which makes them gamble more and then lose what they've won.