der!
> If it's just a PDA, I wondered, why include a cellular chipset at all?
Same reason I tether my netbook and used to have a Vodafone Mobile Connect card in my portable. In fact the very reason for having a smartphone at all, rather than a disconnected PDA.
I have never wanted a mobile phone, only ever a wirelessly connected pocket sized computer. The ability to make calls as well is entirely incidental.
-A.