Well - examples that I regularly encounter on a daily basis:
Phone is in a bag, out of reach.
Specific type of sports.
In a meeting.
Busy area so phone can't be heard in my pocket, but the Pebble vibration can be felt...
Why bother? If people can't see there's advantage to strapping the pocket watch to your wrist, especially when they think people who do find utility in the concept are idiots, I think you're wasting your time trying to convert them. You must have the patience of a saint.
This is such early days and people are already finding utility in strapping technology to their wrists (or more broadly utilising wearable technology). The future in this area is quite exciting, I can't wait to see what they come up with next.
I wear a watch all the time, I love wearing a watch, not because it's a fashion piece (what a pretentious reason to wear one), but because it provides a function that I (and many others who aren't so inclined to wear watches) appreciate. Add other functions to that device that I find useful and I'm there (as long as the device is not unwieldy to wear or use). Fun times ahead, despite what all the naysayers think.