I consider that when things get out of control they will never be a hobby or anything fun , Especially because what is lost is money and that is already something delicate, therefore when we decide to do things right we must have great money management so as not to lose it completely, fun at the casino can depend on ourselves, we can play once or twice a Week , but we should still make reasonable bets and not something that harms us, if we play every day the most probable thing is that we will have an impressive money leak, then it is not something profitable , I would not say that it is a hobby, I would define it as adult fun.
Even if the hobby turns addictive, it still doesn't stop the fact that it's a hobby, it only stops been a hobby when we no longer do it for leisure or fun but for the sole purpose of making money, at that point it's no longer a hobby but an extra job for an extra income, also known as a job on the side. Even with an addictive habit, a hobby remains one only that at they point, it may be gradually turning into a harmful practice that may have some negative effects on the gambler and in the long run becomes a problem for those who are around him too aswell.
Your explanation is comprehensive because literally anything we call hobby is something that is done at our leisure time and for pleasure as well so it depends on how a gambler takes their gambling approach that will determine if they take it as hobbies or depending on it to earn a living and if it gets to that extent, it is no more hobby. Let us not mistake hobby for addiction even though their are similarities between the two words because addiction is something that is done almost every day or every time while hobby is simply things done at a free time majorly for pleasure and fun. Even if gambling is supposed to be done as hobby so that you don't completely get into addiction but however, majority of gamblers don't really gamble for fun but for profit making even though they lose most of the time but their primary aim of getting involved in gambling activities is to win.
Sure when a hobby becomes a habit such that you can't go a day without it then suddenly it will turn into addiction because it has now become something you can't do without therefore it's gonna conquer the fun and pleasure part of it and becomes dangerous.