All diesel has additives added to it at distribution centers, e.g. cetane improvers, additives to improve the wear scar (add lubricity), cleaners, and in some locations at certain times of the year anti-gel additives just to name a few. From my perspective, complimenting a pre-existing lubricity additive with an over-the-counter lubricity additive in order to further reduce the wear scar score (HFRR score) is a good thing.
FWIW, all current BMW gas/diesel caps say "no additives." This absolves BMW from liability or providing warranty coverage if a custoemr uses a product that has not been tested/vetted by BMW if it is determined the additive directly caused damage that would necessitate repairs. Despite BMW's stance on the matter and as I mentioned above BMW dealers still sell a gasoline additive (Techron) wrapped in a pretty BMW label. I guess when they make money on a product it is okay.
