Completely agree with you along with a single caveat.
I do think some of the UX of these devices offer something your mobile phone doesn't but in the name of testing the market, it would make more sense for them to build devices that are currently accessories to your phone, see what use case is getting traction and if a self contained device is necessary.
What I find surprising about these devices is that not only am I paying a lot for the device, presumably because they over-built on software so they could have a stand-along experience, but I also have to have a 2nd SIM for it?
Is everyone paying $50/month for each mobile connection?
