I wear a watch because I always have... from my first Timex as a kid, to Casio calculator watches as a geeky math student, to early smartwatches from Microsoft, Fossil (yay PalmOS, on a watch!), and then a Rolex Air-King I received as a gift (wore that for 15 years)... Moto 360 (I develop Android software), and now Apple Watch Sport since the original release. The Rolex taught me the value of a comfortable, compact, everyday watch "that just works" and has an understated elegance.
Fact is, I like always having the time, in analog form, on my wrist. It's quick to glance and schedule my day. AW added handy things like Day of Week, outside temperature, next scheduled meeting, and some things I never knew I'd really enjoy: answering the phone even though it's on my desk in another room, using Siri to "add milk to the grocery list", setting a 5 minute timer in the kitchen with my hands full, etc... oh yeah, and the fitness tracking is a nice-to-have. On top of that, the AW also ticks the checkboxes for me of comfortable, compact, everyday watch "that just works" and has an understated elegance.
Before AW, my fitness tracking involved a sheet of paper I kept my workout log on (weights and reps), and a pair of running shoes that tracked my fitness by gradually wearing out.
None of these gadgets are required for life, but are nice improvements in day-to-day.
All that said, there's a whole generation of people who just need a pocket-size glass screen that logs into Facebook, takes a good selfie, and maybe play a game now and then... oh and maybe make a phone call to mom. I see few of these people even wearing watches - something the phone displaced like the wristwatch did to the pocket watch, only know the phone IS the pocket watch. So, the pocket watch had it right all along.
I'll keep wearing my Apple Watch, though. It works great for me, and I'm sure I'm not alone in that assessment.