Really now. I understand there might be some small market for "smart watches," but who, honestly, still wears a watch? And who would want to wear a watch that you will (possibly) have to charge daily? This is a watch in name only. That aside, I can see benefits to connected devices such as this. I'm just not sure I'd call them watches.
Well, there's always aesthetics/fashion. I wear a (very attractive, IMHO) self-winding watch. As someone else has mentioned, it's actually really convenient compared to getting my phone out of my pocket, but mostly I like the way it looks -- I guess it's a form of functional jewelry.
I think watches are also status markers. Witness the wide variety of vastly overpriced -- for the actual functionality you get -- watches on the market. A 100$ watch probably performs 99.999% as well as a 10000$ watch, but people will buy the latter, because of the Cartier label or whatnot.
I'd love to say that I'm immune from that, but I'm not. A nice watch makes me feel subtly more powerful. Manly. Strong. In control. Etc... I feel a little awkward without it. This is difficult to explain and may be generational.