You don't have to "be here for the XP" to feel gratified whent he community recognizes you with an award. Be it for your wonderful contributions, 1500th post, etc.
I don't think that any of our active saints are here solely to get karma, that seems to miss the point. I think the point is just to keep things interesting. After all, XP doesn't actually *mean* anything. You'd still have our respect, merlyn, even if the whole voting system didn't exist. If it's just for fun, and for some it add more fun, why not do it?
(Anyway, then we can all stop seeing new "lets add more levels" nodes every few weeks. 8)
...you might be eaten by a grue...