The purpose of the hotline is to help those gambling addicts who needs advise but not get rid of gambling addiction in my opinion. It can be effective though if the caller is willing to listen the advise of the counselors and i don't think they will be stubborn since they called so they really wanted the help they can get.
I have doubts if this initiative is helpful because i don't think that those gambling addicts are willing to share their problems, most of them are even secretive to their own families. As of now, there are no data on what are the number of calls they receive, hope they can release an update on this so that people will know on how this initiative is doing.
If the addict has an awareness then they will probably need help and advice is one of the help they can get either in person or via telephone. It is a different story if the addict is stubborn because they will not be able to accept advice from others even if it is from the closest person.
But the existence of a service that aims to be better like overcoming these addicts is a good thing and should be supported.