I found it helpful, in terms of skills and tools, learning that I could bond with people who have been through addiction and gain wisdom from them. Rehab was a positive time in my life. I learned a lot! It did not keep me sober, because ultimately sobriety is a personal commitment. But even if you relapse, don’t let that make you forget the things you learned! What you learned will still help you.
I think the main point of rehab is to clear your mind of drugs/alcohol enough to let your brain get clear enough to learn a thing or two.