I think it should be illegal in practice because people get into massive downward spirals. Now, that does not mean we need no ban ultra low stakes poker, just the kind of games that cause people to go broke. Aka, someone that loses 200$ a month on poker is not a big deal. Someone that's losing 20,000+$ / month is likely a different story.

I have similar issues with the App Store and feel Apple / Google should limit in app purchases per month.