Playing just for fun alone without considering the winnings is a bullshit reason. We are gambling to earn money and that's the source of our entertainment. Controlling the amount of money that used in gambling is just a method for minimizing the emotional damage once players lose but that doesn't mean he is ok when he loss his money. Greediness is what push us to gamble since gambling is the best source for quick profit, There's a lot game available online if we only want to entertain our self. But we choose to risk our money in gambling to win and that's the reality.
I agree with your opinion, gambling is not betting for fun alone but the main purpose of winning is to make money, gamblers who bet to win will value money will not force themselves on bad decisions all-in without consideration, can control the emotions of greed. While the gambler may have fun it will be the worst in the end, due to the psychological effect upon realizing that he has spent money aimlessly to win.