Well that's a bad criteria. A lot of people get hooked on "snake oil", and will even try to seek it out. Astrology, alternative medicines, crystals, vibes, etc., cults and other such religious beliefs, various social, economic, political and other beliefs that aren't supported by evidence. Lots of them aren't "zealots", they're pushed by fear, misconception, misinformation, desperation, FOMO, hype, etc.
Also, even if some people in some usages get benefit out of it, does not mean that fuels hype and snake oil to try to sell it to uninformed people to use in inappropriate places. Baking soda is good for making bread, lots of people use it for that with great success. It is snake oil for curing cancer, however.