Still, it wasn't like you had to push all the pixels. You only moved 8x8 (or whatever it was) characters. So the C64 was pretty decent, actually. Also, of course you had to shift characters once every 8 pixels.
I was envious as hell on my MSX, which had no pixel shifting at all.
It’s very helpful and the implementation is ingenious but not very complicated.
Vertical scrolling changes the timing of the bad lines and horizontal scrolling the timing of the bitmap data fetched and this causes the image to come out at a different position.
There are a lot of creative tricks you can do with this though, especially with vertical scrolling.
I was envious as hell on my MSX, which had no pixel shifting at all.