after a certain framerate, the difference is imperceptible to our eyes. i.e. 60fps looks the same as 120 because our eyes aren't good enough to notice a difference i guess i didn't word that too well initially lol
I think its more a myth tbh, from when TV was standard 30 fps. Anyone can see higher than 60 fps, its just that the frames become harder to distunguish individually, which is what leads to the smoother feeling from higher framerates.