This is quite dangerous, you might need to check yourself whether you are already addicted to gambling or developing gambling addiction. I hope you do not fall on the both situation and still have the control over your gambling activities.
In my gambling activities if ever I hit my target winnings, I withdraw all my funds and allocate a certain percentage for another session (specifically the same amount of my initial bankroll). I withdrew all of the fund to limit myself from playing continuously and to save them for my next scheduled gambling session. This works fine to me because I am able to moderate the time of my gambling activities while saving me to spend more money for my next gambling session.
I agree that the real winnings in gambling is the amount of money a person can withdraw and use for another purpose aside from gambling activities. But if the person is able to entertain himself, and had fun in his gambling session (without getting addicted to gambling), I think it can be considered a win - win situation for both the players and casinos regardless of the outcome of the players gambling activity.