IMAX did tests back in the day with footage of a baseball being pitched directly at the camera. They found that the intensity of emotional response tailed off after 60hz. It's not that the higher frame rate isn't perceptible, but that raising the frame rate doesn't really have any appreciable impact unless people expect higher frame rates.

I know this isn't what you mean.. but I'm imagining someone blindfolded in a research lab testing this out...

I can see benefits even while scrolling a webpage or moving windows around. It's very confortable.

This been said, I can remember CRTs at 60hz with side scrollers and demos at 60fps with perfect image stability while scrolling. You could read tiny texts scrolling up and down perfectly. This is not the case anymore with LCD panels...

Try to read a webpage while scrolling, impossible.

60hz or 120hz I would pay for a stable image in motion. It would bring tremendous confort.