Self control and discipline is what make the difference. You can be a successful gambler and still be an addictive one because it all depends on the way we utilize it and from what angle we are seeing it. Gambling is something we need to understand and what it take someone to be a successful one. When we have become a professional with results, we can be called a successful gambler either an addictive one or just a discipline one. When we want to make profits by all means as a gambler, we might be tempted to do the wrong thing becoming an addict.
At the end of the day the odds are against you, and being self controlled and disciplined won't make a difference.
It's all just probabilities in the end. You might have one person that hits the jackpot at their first try, while another diligent one never wins it.
Self control and discipline wont make a difference in the result/outcome (win/lose) indeed but it will make a big difference for our whole gambling journey. Without self control and discipline, you might be down badly and affect your whole life emotionally and financially. This is for me what is called by "successful gambler", gamblers who can play gambling as they wish and it does not affect their life negatively because they have self control and discipline in managing their money and time for gambling.