I guess it depends on what you mean by “Rehab.”
My lower back was super shitty and weak. As a result, I would often “injure” or “hurt” or “tweak” it in training when I tried compound moves like squats and deadlifts. Over the years, my lower body training got worse, and less consistent. This made me weaker, and made my lower back “worse.”
When I finally jumped on the Reverse Hyper, I was able to Target my lower back. It was the “main mover” in the exercise. I could select exactly the weight I needed. It was an isolation or assistance move for 1 specific area. I started with like 70 pounds for 3x10 or something like that. A year later I did 270 x 4 sets of 25.
As my lower back got stronger, it felt better. When it was no longer the weakest part of my body it stopped hurting. Finally I could train my lower body again! So for me, it worked pretty well.
My girlfriend didn’t have any specific problems with her back, but her squat had kinda leveled off. She started to round over a little at the bottom. So she got on the Reverse Hyper. In a few weeks she went from using 50 pounds to using 90 pounds. She was able to add about 20 pounds to her work sets of squats during this time. So it worked for her too.
Some people at my gym don’t like it. They complain about the “lower back pump.” But those same jokers would pee their pants if they could get pec or bicep pumps like that.