Respectfully, I disagree. It about having a sufficiently good refresh rate so that the VR world "feels real".
I understand your point, more than most. Years ago, my "personal superpower" (or defect) was that I could EASILY see the difference between CRT monitor refresh rates: 60, 75, or 85 Hz. I astounded my coworkers by being able to tell them their refresh rate with 100% accuracy. No one else (of ~70 people) could tell the difference between 75 and 85 Hz, although some could detect 60 Hz monitors. The downside is that I found it draining to use the more common 60 Hz CRTs.
That being say, CRTs are very different from LCDs. I have no trouble with using a 60 Hz LCD monitor, because of the long image persistence. I'm willing to believe that 90 Hz is important for a rapidly flashing OLED screen, but an LCD screen might not have the same problem.
TL;DR I don't think we should be too concerned with the current 80 Hz refresh rate, until the M1 testers have a chance to examine the units and give us a first-hand report. If they feel it's an issue, Pimax will hopefully try harder to find a 90 Hz solution.