While true the problem is going from not controlling yourself when you gamble to actually do so can be extremely hard, after all those unbridled emotions they may feel when they gamble with money they cannot afford to lose are something they are not going to feel at all once they control their gambling behavior, and in that case they will always be tempted to go back to their old habits, and for someone like that it may be a better idea to give up gambling completely before they do so.
If they lose self-control while gambling, they can forget to take care of themselves and will instead be tempted to continue gambling which can cause them to lose all the money. Even though you have allocated the money for gambling today, but because you lost self-control, you forgot and used all the money instead. That is a mistake that we must correct immediately so that it doesn't happen again in the future or when we gamble again. We must be able to resist the temptation that comes in the form of attractive promotions provided by casinos, especially if we really want to limit our gambling time.