Cold turkey is good and if one can sustain it, shows their willpower is strong and these people will recover faster than the ones who relapse into playing again.
It is difficult to keep the temptation of making money easily as the false hope and greed tend to bring us back to the cycle of loss and chasing the loss. We are all slaves to these habits and hence it is difficult but can be overcome with determination.
Getting addicted and then the deaddicted is a tough process indeed but it can be done and people have recovered from gambling addiction.
I am against any kind of absolute restrictions. If you like something, first and foremost you need to learn how to coexist with it, not try to cut it out of your life. Later, things can get much worse when you fail to hold back and lose control. I am not only talking about gambling now, but also about other habits of ours that can sometimes lead to addiction. If you like something, learn from the start to control it and keep it within reasonable limits. This is much more effective than restricting yourself and then breaking down.