It's all about self-control and money management IMO, and with that, you can be safe from doing other "stupid" things as well. Even with trading or investing, these two things are still crucial.
Anyway, I learned it from my uncle. He should've been one of the richest guys in the town, but his gambling problem turned him into just an average guy. Imagine what will happen to average Joes? Yep, debt and forever poor.
If you are the type of gambler that learnt from other people's mistakes then you are lucky because this isn't something that a lot of gamblers can relate to, some gamblers had to learn the hard way but I feel like those lessons won't be valuable if they don't experience it themselves. Just like you said, self discipline is key and without it gamblers would easily fall into doing a lot of stupid things
Yes, if a gambler can control himself by learning from another gambler, then he will be luck because in most cases, learning without own experience is not very effective. For a gambler who can learn from gambling and improve himself after losing, that education will be very effective, but it is natural that someone who has not yet gained any knowledge on his own will not be able to achieve that much. Self-control in gambling is a quality without which the gambler is more likely to lose. Before gambling, it is necessary to know the knowledge related to gambling especially how to manage self-control in gambling.