Yup that's the point, maybe I can say that the real victory is gambling is when you are able to use and enjoy the amount of victory for whatever you want outside of gambling, such as going to the cinema with your partner or going on vacation with friends or family to enjoy the amount of victory you managed to get.
This means that even if you manage to win a large amount but on the other hand you can't enjoy it and instead use it again to gamble then it's not a victory, it's just deposit money and after that the casino will take it back.
This is the reason why gambling must be done intelligently, because when a gambler treats gambling blindly without any management and limitations, even though they manage to win but in the end they will still lose that amount in the same place, making a withdrawal after successfully winning will always be the best action that must be taken by a gambler.
Sure you are right on what you are saying.
People do not understand the reason why it important to withdraw your money immediately after winning, thou they might feel like still reserving some percentage towards gambling site to enable them gamble without having to make deposit. But to me someone victory in gambling is the winning and they were able to make withdrawal and spend the money on more important things than reserving them back to gambling site and used them again to gamble. This is more like give and take, meaning they are giving back to gamble site after having managed to secure winning from their long term gambling challenges.
Yup of course that's the point and as you might expect it seems like they really don't know about the benefits of cashing out their winnings from the start when they win, but in this situation there are two possibilities that make them do that which could be they also know that cashing out is the best action to take but because of their high obsession with winning it makes it difficult for them to control themselves and ultimately continue the game.
On the other hand, setting aside some of the winnings to continue gambling and then cashing out some of the other amount is also a good method but actually it can also potentially cause curiosity and a desire to continue when some of the amount you use to continue gambling turns out to be used up due to losing, honestly I've experienced it.
So actually there is nothing better to do in a winning situation than cashing out the entire winnings and enjoying it for various things you want like shopping as you said.