Good question. Just note that success is not the only possible desirable outcome. And I would judge it at a larger than individual scale, sort of like a medical

Good question. Just note that success is not the only possible desirable outcome. And I would judge it at a larger than individual scale, sort of like a medical trial for a drug. I think no, there's no proof it actually does anything meaningful. Otherwise we would see some effects on populations where these practices are popular.