So plain, non-fat yoghurt is just as good?
Yogurt has its own set of probiotics, which have different qualities. The particular microbe they are studying seems to be in kombucha but not in other fermented foods or drinks.
It has been good to me for 80 years. No bowel issues whatsoever. My mother used to make yogurt every day with leftover milk. She just added a spoon of yogurt to pot of milk before going to bed, next morning the milk had become solid yogurt. Those yogurt bacteria multiply fast obviously. And they overcome bad bacteria in gut.