What is the advantage over broadband systems? Most people who live in an area populated enough to get a Sprint wireless signal would have access to cable or dsl. Why not go with Vonage for $20/mo, or Ooma for a flat $150 and no monthly charge?
This seems in direct competition with their investment in Clear, but with a much better use case.
It will also cut into my mobile bill, because if this can operate on batteries for ~2hrs, how often do I really need to use my cell phone?