There is more to it than being able to "see" the pixels.
Take a cellphone, they have HD screens, and look super clear no matter how close you get.
Then look at something like an apple Retina display (2k) or a new skylake tablet with a 4k screen, and it is amazing how much you CAN'T see the pixels. You can't see the pixels in a photograph, but that doesn't mean a 1200dpi scan isn't any better than a 600dpi scan, because it is.