I've had my Space Gray Sport for not quite a year and a half, have bumped it into innumerable things, and yeah, if I examine it closely with a high-intensity flashlight, there are a few microscopic marks in the finish around the glass - and from a foot away in normal use, they're basically invisible. This is completely normal (and that edge is more likely to get marked up because it comes up to a very thin edge around the screen - so the metal and its finish are at risk from multiple angles - and it's a little closer to the real world, so more likely to get bumped). There is no paint involved, by the way, the finish on Apple's aluminum devices (the ones that aren't shiny silver, anyway) is
anodization. The wear happens on the lighter colors as well, but since the underlying metal in all cases has a shiny silver color, it's much more apparent when things are anodized to darker colors (shiny silver blends in much more easily with shiny light gold, light pink, etc.). I have a lot of other anodized tools (like high-end flashlights and pocket knives), and they all show wear when they get used. If you want a black watch to look perfect forever, put it in a display case and never use it. If you use it, the finish
will wear. No finish is perfect (titanium nitride and DLC come closer, but we're still a long ways from perfect). When I look at my 17-month old Apple Watch, I see a colorful and informative screen, a glass front with zero scratches, a dark gray body and crown, and a colorful band (light pink and mint, today). I
don't see the fraction-of-a-millimeter wear spots in the finish of the aluminum around the edge of the screen. Because they're minuscule, and I don't normally wear a jewelers loupe.
White ceramic, by the way, is kind of a perfect material, because it doesn't mark up, and even if you could scratch it, what's underneath is... more white ceramic. It's fantastic right up to the point where it chips or shatters (because it has such high hardness that brittleness comes into play).
As others have said, uncoated stainless steel and aluminum (such as the "silver" aluminum Apple Watch) will naturally make surface wear much less evident, since there's no dissimilar finish to abrade, just the base metal, which can be polished or sanded to smooth out any damage.