I do like the idea of the physical KB, though I can't imagine many would carry both this and a phone.
Nope. The Kindle is for content consumption, and he's trying to position the Communicator as a content creation device (i.e., with the emphasis on sending stuff rather than receiving stuff), so his analogy doesn't work.
What he should have said is that Communicator is to a smartphone what a laptop is to an iPad. That would emphasize the physical KB, and the focus on content creation.
Though to really be a content creation device, it needs something like Office, which other commenters have said it doesn't have.