Besides NS coatings, some products appear to have so called powder coatings. What is the use of these coatings?

A powder coating has more or less the same properties as the NS-coating. In the production process, talcum powder gets rubbed onto the surface of some products to fill the small pores of the material. This thin layer will make sure that the material does not stick to itself or to human hair. Its stickiness is comparable to that of an NS-coating: just enough so you feel in control of the product.