I'm mostly with sliverstorm (and upvoted him). People often wonder why I'm working on a 13" Macbook and ask if the display isn't too small. That's when I point to my head and tell them that's where the action takes place, not on the keyboard or the screen. (Obligatory: http://www.folklore.org/StoryView.py?project=Macintosh&s... )

That said, decent ergonomics are almost always a good thing. Even if you're not typing a lot, you'll probably still spend a lot of time looking at the screen. Having a bad setup maybe doesn't matter for your wrists in this case but it can still be detrimental to your eyesight and of course your back.

Maybe that's why sliverstorm got downvoted: there are good reasons to care about ergonomics even if you're not typing a lot.

(For what it's worth, my excuse is convenience: I'm working in lots of different places and I can't be bothered to lug around a huge notebook or an external keyboard. Before the age of notebooks I used to have a fairly ergonomic setup with a big screen and the awesome 1st gen Microsoft Natural Keyboard, and I often do miss it: maybe I'll return to such an "immobile" setup next time I have a job with a desk.)