You can do very slow yet smooth scrolling for games by using the subpixels - at least on platforms like e.g. the Game Boy Color where you know the pixel geometry. Of course you need to use 'whole' pixels (composed of RGB) so the perceived color doesn't change.
In the games I make I always track positions at a subpixel level and then I can choose whether or not to draw things with that accuracy depending on my needs. I might want a shape to move more smoothly at a sub-pixel level, or round things to whole pixels. Both ways are useful for different reasons or in different situations.
I do think there's a really interesting alternate world in which we never invented the colorpixel, and image formats instead were represented by an array of grayscale pixels with a repeating color mask.
