When I'm quickly trying to find a bookmark, it's easier for me to find the ones with distinctive colors. I've actually rearranged my bookmarks toolbar at times

When I'm quickly trying to find a bookmark, it's easier for me to find the ones with distinctive colors. I've actually rearranged my bookmarks toolbar at times just to get better separation between similarly-colored favicons. So IME there is a singificant advantage to having memorable colors to the icons; they're easier to find.