Setting win limits is a very important task among gamblers. Some gamblers continue their gambling activities even after receiving more winnings or bigger wins.
In as much as gambling is concerns we shouldn't place all our focus on gambling, or using all our money on gambling with the hope that it will work for us and perhaps if it eventually fails it becomes a setback for us, but perhaps having a job could also help our mindset in times of gambling were as all the attentions will not be channel only on gambling but for other things too, also with that someone can easily control his method of gambling or perhaps just like you said it will also be good if we should set a target of wining or losing that whenever you losses or wings a certain amount you should call it a day instead of betting beyond that.
Someone who has a good source of income,. Be it business or job will likely have moderation in gambling than someone who doesn't have a steady income. Someone who has a steady flow of income is likely gambling in order to have fun or probably may be gambling to augment his earnings. This cannot be said about someone who is strictly gambling to have huge money.
Setting a loss limit is what will help you as a gambler not to lose more than required or necessary.
In terms of winning, the casino have already limited you, setting another winning limit by yourself for yourself is simply you limiting yourself further, this is completely not necessary if you ask me.
Setting a winning target is the right term and not winning limit. They might mean the same thing but when we use the word winning limits, it doesn't make so much sense because the casino had already limited the gamblers according to you. If we set another, it is putting ourselves into an unnecessary pressure.