This isn't true generally. I am personally far more comfortable with disabling smooth scroll. It has more to do with your mind's expectations. Which can vary between people. Some people expect smooth and others don't. Motion itself isn't necessary.

The only time I have to "rescan" is if I input a scroll and anticipate a scroll and it doesn't scroll. It has nothing to do with motion. In fact, in that case, I "rescan" even though the page hasn't changed, but because it doesn't match my expectation that it would change.