Nothing in the Wikipedia article sounds surprising to me. The Wikipedia article says nothing about him achieving therapeutically useful effects with it or claiming to do so.

I have two friends who successfully cured allergies via hypnosis. One of them found that it takes motivation on the part of the subject and doesn't work well when the subject doesn't pay for the procedure so an attempt of doing a formal scientific trial failed due to the recruited subjects who got the treatment for free being not motivated in the right way.