you've said it all, self exclusion doesn't really break addiction totally because at anytime gamblers can decide to create another gambling account. But what works for one might not work for another so I wouldn't really call oy a pointless feature because some gamblers use it to restrict themselves and it actually works for them. it has a lot to do with discipline and deciding not to gamble for a while
Aside from deciding to create another gambling account, I don't think it's easy for addicted gamblers to stop, even after self-isolating. However, there will be a compulsion that keeps them wanting to gamble, and they'll then find other ways to continue gambling.
However, for gamblers with strong self-awareness, I believe they don't need to self-isolate. If they're truly aware, they'll stay away from gambling. This is more about individual self-control. But self-isolation is also a way to achieve positive results.