Your view of gambling as chilled-out leisure paints an alluring picture but not without risks. Things get messy when the initial excitement of risk-taking turns into a fixation. Saying that only a few gamblers can stay in control is a big understatement. Many studies reveal that most people can't recognize when they've shifted from a good time to an addiction. Their brains link the thrill of the gamble with happiness, complicating quitting. Though gambling for fun with self-restraint seems feasible, it overlooks the potential destruction of addiction. It's essential to highlight that for many, gambling isn't a simple toss-up between enjoyment and gain. It's a psychological trap causing deep financial and emotional issues.
That is a good description, but there are also no definitions and you either realize when it is too late or you allow someone else to tell you. But in most cases people don't share their activity the same as they don't share when drink alcohol secretly. The difference is that it is easier for someone around you to se whether you have an alcohol problem in contract to when you have a gambling problem. it is the same for any addiction and there are no general thresholds or rules. Someone might get along quite well with wasting an entire weekend on gambling, not losing existential money and still feel ok whereas for someone else it is already an existential threat to neglect social relationships.