I don't have a dog in this fight. I have no interest in changing your mind. You just asked a question and I was trying to answer it.

People that take supplementing seriously tend to try to measure the effect by getting regular blood work done. That's prone to all kinds of uncontrollable confounders naturally. Regardless, it's a risk-reward thing for most people and they don't mind the expense if it means they'll potentially be healthier.