I could find a tablet useful as a photographer. Maybe it isn't where I make critical color decisions, but in theory there should be nothing stopping the tablet from being quite useful as a touch-screen hands-on road tool for viewing mass thumbnails, rating and keywording via clicks and drag/drop, organizing client galleries, uploading to photo web sites...
Heck if Apple does it right, it might be fun to do all that on the tablet. You could, in theory, build a killer multi-touch app that works like the old-time "slides on a light table," lightly nudging virtual "chromes" around with your fingers, but with all the advantages of digital gestures/shortcuts for labeling, rating, rejecting, etc. We've all heard from photo veterans who feel more disconnected from photography these days having to go through mice, dialogs, and sliders to work on their pictures, who miss the old hands-on way of working with photos.
Maybe the tablet can bring some of that back.