Well you are right , self-control play a vital role in gambling, which may help to minimize losses when gambling. Because we all are aware that losses cannot be avoided or neglected, but one can manage his losses by having a good self-control. This the thing most gamblers lacks in this space that's why there are alot of sad stories how one lose a certain huge amount amount of money, for instance one would have lose only just small amount of money but due to not knowing when to stop .
I think Practicing self control is easier said than done, I say this because a lot of gamblers knows too well that gambling without self control can ultimately have disastrous outcome. And every single time they plan to gamble, some would always try as much as they can to prioritize self control over gambling with emotions, and every single time they find themselves losing control. So it's not just a matter of knowing the importance of self control because many gamblers have already experienced the effects of lack of self control and yet they still apply emotions whenever they gambler and end up regretting at las. Would you still say this is caused due to their ignorance of the importance of self control?