It’s true,people should split their income to different parts every month.The gamblers should have allot 10-20 percentage of money for their entertainment,So the entertainment money will not affect your monthly expenses.This was the strategy to get away from any financial issues after the loss from the gambling.Gambling profit always give you some good enjoyment and allow you to buy some more desired items.But we should think about the loss too.Because being practical will lead to peaceful life.Some of the gamblers failed to calculate their income and living the peace less life.Once you do planned expenses,you will be free from credits.
You are indeed a rich dude/person for allocating such 10-20$ to gambling but to me, I feel like its a waste when I have more responsibilities to tackle but its cool, you may have little bills to handle and more time to have fun but I don't have money to spend on gambling. The reason why I said so is that my wager is always in local currency and considering the siuation of dollar rate here, if I use that % on gambling, it is going to be a extravagant life style that may end me up with gambling addiction.
If you have lots of financial responsibility and your income is somhow enough for theses responsibility, I think you should avoid gambling since if you lose the little extra you have, you might get tempted to use the money that you can't afford to lose. It is really a good thing that you see those small amounts of money being wasted when it was lost on gambling since that shows that you value money and do not want to waste it on something you think is not worth spending.
I also agree that @OP is somehow new to gambling activities since his experience and statement shown a not experienced stance and some confusion about the term "money that is afford to lose". I believe with more experience in the gambling industry and reading more information about fallacy, guidelines, gambling terms explanation, @OP will eventually realized the misconception or misunderstand he has when he created this topic. He then probably come to realize that gambling only the money we are afford to lose is actually one of the best practical advise one gambler should listen to.