I would use it around the house. If I'm doing development, yeah I'll use my laptop, but if I'm just watching movies and surfing the web, why wouldn't I use one? Currently it's not unusual for me to sit in bed using my iPhone and apps for internet access for an hour or so.
I would also use it in my car. I'd like to mount it on the console and hook it up via Dock Connector as my removable in-car computer for navigation, entertainment, etc.
I'm not in any rush to buy one, but if I felt like I wanted one, yeah, it wouldn't be collecting any variety of dust.