Does regulating the health professions help patients or these disciplines?

Depends. As a patient you might want your doc to have gone to medical school. You might want the drug addicted ones to be removed before their impairment causes you harm. You might want the ones treating you for cancer you don't have to be caught and go to jail. There are many complex issues in this process the public never sees, but the health related boards make the effort to remove the bad actors.
Depends. It is supposed to help patients - protect patients, but regulations are enforced at such an arms length away - there usually is not a lot of actual benefit to patients.