Does it really help them? No, and I don't think they need to do that just for the sake of stopping people from becoming a gambling addict. Instead, they keep encouraging people to gamble on their site and enjoy themselves.
Honestly, being addicted to gambling is not about the site, it is about losing control of ourselves. Though they are saying just gamble moderately but in the case of addiction, they have nothing to do with that but to let them play, instead of stopping them.
Gambling addiction is certainly a choice. If you see yourself experiencing it, then you should be responsible enough to stop gambling and avoid gambling at all cost. And not that gambling sites are given responsibility to stop them because honestly, it will definitely not work. Gambling casinos are designed to make money from gamblers, and not that they should stop them from playing whenever they have lose huge amount from gambling. If gamblers will chose to continue gamble and lose their money, that’s already their problem and not on the casinos.