I purchased this for a camera that I seldom use. It still is a valuable collectors item that I want to keep in excellent condition and that means I needed to protect the lens. I only have filters with the Zeiss "T" coating constructed of German Schott glass on the cameras I use frequently, because I consider them the best multicoated filters that I can afford but, I cannot spend that kind of money for a camera I use infrequently.
Any camera that is threaded to accept a filter deserves the protection that comes with a mounted filter in front of the actual camera lens. I would rather risk damage to the AR coating on a filter that can be easily replaced than risk damaging the actual lens on any of my cameras from cleaning, and exposure to airborne dust or chemicals.
This brand of filter came carefully packed and the filter holder included with the filter is well designed and provides excellent protection for the filter when it is not on the camera lens because I am using a different type of filter. This filter has multiple AR coatings on both sides of the filter and after comparing the results of identical pictures with the same camera using this filter and one of my prized and now unaffordable Zeiss "T" filters I can say that I can see no difference in the results. I am sure an optical lab could document some differences, but in the real world, I can see no differences when comparing the test pictures I captured through this filter and the Zeiss filters I have used.
This design works so well, I will slowly replace the older non Zeiss filters I have on my older lenses and cameras with these newer designs.