If you have mental illness, getting help for it is commendable. And it's worth it because, with the help of mental health providers such as therapists, psychiatrists, etc., you can overcome it and live a happy, productive life.
Also, doing what you can to help yourself while you're in treatment increases the chances that you'll be successfully treated.
However, if you get the help and do as much as you can to help yourself in the long term, you are not only helping yourself. You are also helping those around you who care about you, such as family and friends. It will give them a good feeling knowing that you're getting better and that you are doing your part to help yourself.
It also helps mental health workers/professionals who are trying to help you. To them, knowing that they can help people, such as yourself, who have this terrible illness makes it all worthwhile to them.
So if you get treatment, get better, and help yourself, you are not only helping yourself. You are helping those around you as well.