Oh, don't get me wrong, I go off names too. It's just that the avatars help me map a name to a person, at least for the first few encounters I get with them.
Put it this way, it'll help me remember you someday if we run into each other again. I'll be honest, the more accustomed I get to this place, the less it's necessary, but there are lots of not as regular members here. For them and even for me, little fun pics help.