Let me counter your anecdote with mine. I talk with customers all day for project related work. I regularly put thousands of minutes on my phone each month, mostly for work.

There's literally no way that today's battery density (or even in several years) is high enough to support more than a dozen calls, not to mention all the radios a cell phone requires (just think antenna length, not space).

I wouldn't expect a viable standalone phone-watch until 2025 barring significant advances in battery technology and cell antenna design.