Hi Kat,
+1 to POTAWIE and Salsa Lady.
The health benefits are that the Lactobacillus bacteria that we use to ferment the mash with are a Probiotic. We already have it in our guts and assist us in digestion. However, only if the sauce is left uncooked as heating the sauce to the boiling point kills any and all bacteria. As the mash will be, post fermentation, at an acceptable ph, mine is usually at 3.4 right out of the fermentation jar, there is no need to add any acid to the sauce except as a flavor component thus requiring less needing to be added. This saves money in production of the sauce and more control over the flavor profile. For many it is purely a flavor issue. There a lot of people who don’t like or who prefer less of the vinegar taste in sauces. This probably comes from the over use or perhaps abuse of Apple Cider Vinegar in sauce making which has a very strong distinct taste and can easily take over anything.
POTAWIE is correct in that it mellows, meaning that is helps to soften any really sharp flavors, the sauce and allows all of the flavors to come together. This may be in part due to fermenting allowing us to age the mash for several months to years but I believe, IMHO, that the fermentation process of converting sugar to lactic acid has something to do with it too. There are also some ways that fermentation allows us to play with the flavor profile of a sauce. For instance, when I make my Jamaica Me Hot Sauce I use a lot of sweet ingredients such as Golden Raisins and Pineapple and yet it is not a sweet sauce. While the sweetness is gone though, the flavor and aroma of those ingredients remains as part of the flavor profile. This allows me to develop very complex flavor profiles that really play and dance on the tongue.
I hope this has been helpful and while not based on scientific facts it is what I have observed in my fermenting peppers.
Cheers,
RM