A couple of uses I personally could have for it: one is for ad-hoc presentations with a couple of people where they haven't booked a proper projector - we usually dig out a spare screen from somewhere, but this would do the job with much less hassle.
The other is along with a pocket keyboard, for when we're installing our trial servers in data centers and need to troubleshoot on the console - occasionally our customer doesn't have a KVM they can hook up - and this is a small, quick stop-gap.
I saw one of these being demo'd in London City Airport today. It didn't look that bright, giving a legible 14-inch-ish display in moderate ambient light - but for a meeting with 2-4 people who would otherwise crowd around a laptop screen, it'd do, and the price point isn't restrictive. Combine it with a VGA-capable PDA like the Touch Pro that I just got, and you can see the attraction. I think I might buy one.