If you have self control then gambling can be a good way to make money for you and there is nothing wrong in gambling until the people around you are not aware about it but if they come to know that you are a gambler then it can spoil your reputation in public.
Wether you are having a good self control or not, it is not really going to help you in making some money. Afterall it depends on your luck, so it doesnt matter if you have an epic self control or whatever because it wont be helping you at all. People are stupid to think that they could get profit when they control themselves