As mentioned, it is a pH adjustment, but it also has a flavor contribution. I'm a firm believer that lactic acid as pH adjustment also adds something flavor-wise to a pilsner. In this case, it's going to have a more complex contribution, just as a kettle sour tastes different than pure lactic acid added to beer.
That being said, I personally dislike the strong grape flavor that you sometimes get in a light German beer. I haven't gone the sauergut route yet but may try it in small quantities to see if I like it.