It is necessary. There is no such thing as a non-dusty environment unless your in a boat on open water. I see you ride an Ultra. Try riding behind a car or truck without a windshield. You will quickly see how much sand & dust there is flying around you on what seems to be a picture perfect day.
The key is to lightly oil it. The whiskers on the filter material won't be able to vibrate in order to catch dirt if you over oil it.