Small study, probably not preregistered (didn't find anything about it in the description). Likely Publication Bias or p-hacking. I'm starting to get interested when it's been independently replicated.
This is becoming an increasingly worrying trend - to bunk any analysis with a comment on 'small sample size, biases' that somehow moves to the top of the comment pile. Statistically, there is no such thing as a 'small sample size', in isolation. It is always related to the power and effect that the researchers want to work with. Moreover, even if a study is statistically insignificant, it DOES NOT mean that the oppos…
Lots of things that are completely useless have been used for thousands of years for their medicinal purposes. The evolution argument only holds if there were some negative effects here. Anything that doesn't do harm to the body can easily integrate into the huge body of knowledge called superstition. Eating it is tasty and doesn't hurt, there's nothing more needed to explain that Asian cultures have it as a medicinal herb.
If it for example was good for you but caused somewhat unpleasant side-effects, your evolutionary argument might have more merit. Anything that works as well as homeopathy (it doesn't), but doesn't harm either (like homeopathy), won't be sorted out.