Concerning the time period of the USAF test it obviously doesn't matter.
Concerning the blur you are arguing a completely different point. Rather than a blur created by a hardware persistence issue (I would call it optical nerve ghosting except it sounds like it is at least partially the blame of hardware) the motion blur on the periphery created by software is a tool to help battle user sickness. These are two totally different things. It's not just for VR either, but also has a place in any display environment where high speed motion in close proximity with fixed objects, or objects moving in the opposite direction could instill motion sickness.
The whole point of an option like this is that it is an option. Since not everyone reacts to MS (similar to Frenchy) in the same way it will not be a cure for everyone, but what bothers me most about these devices is the 20-40 minute limit recommended by the manufacturers.