I agree with you. All I can think is that it's affecting some central mental or physical aspect that has many different outward benefits.
https://news.ycombinator.com/item?id=45907422 (citations)
(i am hopefully that probiotics might be a future path to curating gut microbiota that meets an individual's GLP-1 in vivo production needs based on target metabolic outcome, but immediate intervention is welcome for obvious health reasons at scale)