Yeah, I've seen tons of stuff like that. Yeast, milk that's out of date, various bacterial and enzyme products etc.
Bottom line, (pun not intended), is that for the most part, just putting only what belongs in the septic tank in the septic tank, (and keeping the filter, if there is one, hosed off every year or so), will keep the system running to the point that many folks don't even need the tank pumped.
When I was researching the topic, I had email correspondence with some scientists that conducted studies on the subject at a university somewhere in the Midwest. I no longer have the correspondence or I'd share it here for those who may find it of interest.
In any case, anecdotally, we have gone 17 years without any sort of supplementation. But folks are gonna do what they're gonna do.