My small experience of this, apart from working with a stage hypnotist, was a single session, during which I was made to relax, nothng more, and as a result of what was said to my surprise then and there kicked a smoking habit of many years duration. That was in 1976, and I have never touched tobacco since. The 'therapist' was a retred Army Colonel, who did it as a hobby, and charged me £2.10p (two guineas!) which he sent to charity.
Hypnotism requires a sort of contract of trust between you, and can't be imposed against your will. It's not magic or spiritual or any other kind of supernatural flummery.
I see mention of a dentist's use of it above - someone I was at school with became a RAF Dental Officer, and he found it a useful adjunct which he carried on into civilian practice.
'Regression' is baloney...!