We could talk about whether the The Magnuson-Moss Warranty Act would come into play depending on the warranty claim being filed. That is, should one ever need to file a claim. For the sake of discussion, lets assume the end-user didn't care about the warranty and just focus on the technical aspect.
Here I'm not really talking about the hardness of the coating. I'm talking about the lubricity of the coating. As we've found, GPs need to be run wet, especially around that area. Coatings like NP3, DLC, etc... have dramatically low coefficient of friction ratings.