Protection of materials turns to be the key to make a new product successful and market-acceptable.
This happens to be important for 2D flat materials (e.g., plastic films, touch screens, glass, alloys, etc.) as much as for 3D complex objects (shell of a car, 3D printer-made parts, museum pieces, etc.) that need protection against abrasion, dust, pollution and any kind of physical damage.
In most cases the protective coating must not impair the display of the object, rather it should improve it, for example providing higher visibility and better appearance, which means increasing transparency and gloss.