In reality in this world wherever we go we encounter losses especially in gambling we can not say that always our by will win cause there's a time that we are unlucky and we will loss our bet. So it's better to have self control and be responsible in gambling. Spending money must be a good budget and it's better to gamble in your existing money it because if you loss you won't feel a very bad thing.
That's as true as butter in milk. The gambling is a freeway to wins and losses and sometimes we will have to face many losses even if we are doing our best. A gambler is putting everything in search of winning but sometimes the inverse can happen and instead of winning they can face consistent losses.
It's a better practice to have self-control during gambling because if you're loosing a lot then you should stop betting because sometimes the luck isn't in your favor and the losses can be high if you don't stop. The gambling is not for everyone and the ones who have no control over their emotions will lose in this game.
I agree that the gamblers should spend only the money they can afford to lose because if you put everything that you own into gambling then you're doing that to make your life worse. Never every put the money into gambling that's important for your sustaining and if you do so then the consequences will be adverse.