Or does any watch company use such a feature already on their crystals? I googled and can't seem to find any.
I know atleast Samsung uses this on some of their smartphones, and some aftermarket companies offer screen protectors that have such a coating that is anti-smudge.
I had a Samsung Galaxy that had this feature and it was EXTREMELY effective in repelling smudges. I let my nephew use that phone often and the back would be completely sticky and filthy but the screen was spotless and smooth.
I know countless WIS that have a compulsive habit of constantly rubbing their thumbs over crystals to remove smudges, even phantom smudges ( I do).
I have found that Dow Corning offers such a coating that is also used together with anti-reflective surfaces.
I figure the biggest question would be how durable are these coatings for watch crystal use.
Would you like this as a feature on your sapphire watch crystal if the coating would not be prone to visible scratches?