1) if such program was already existing in casinos and other gambling sites globally, perhaps it would have saved Phil Mickelson from the five years of huge financial loss
2) it would have saved him from any health hazard or frustration he might be going through that he has to go for a therapy.
The if statement is still conditional. He would have gone self-exclusion if...
1. He knows that he is already a compulsive gambler.
2. He wanted to treat his addiction
3. He is very very serious to treat his addiction.
Even with the self-exclusion tools being present if he failed to identify that he is a gambling addict and in need of treatment then it won't help anything. Aside from that if he is dead serious about treating his addiction, he could have looked for a medical expert on addiction to cure his gambling problem.
So with such program implemented it's really going to be helpful for many gamblers will know when to apply some breaks. And certain mistakes of the past can perhaps be avoided.
Even with the presence of this tool, I don't think there will be any difference since the online casino today never checks their user's gambling conditions. In our experience in online Casino, had we ever received a message that the self-exclusion tool is available on the site? I bet no.