Will expand when I get to a keyboard but K/D is a number I look at my for my own game. I know how I play, I know I play to win so that number has context for me. Other people's K/D, SPM, W/L doesn't interest me in the slightest. There are some good stats out there that are better indicators in to someone's skill but those generic ones on show in COD aren't great.
I have an account in Black Ops 2 with a 4 K/D and a SPM of 430. If stats were as important as some people made out then I'd be swimming in clunge.