"most people hate wearing stuff on their arms, wrists, and other body parts, without some mandatory utility". I think if you do a little anthropological study you will see that man has always had a fascination with wearing things on (or through) their body. Jewellery, earrings, piercings, bracelets, crowns or head-dresses, neck ruffs, broaches have all been used to help establish a person's identity in a group rather than serve some functional purpose. So I would place the Apple watch more in a social than functional space. The person that buys the $20,000 gold Apple Watch says something to the owner that is probably far different than what we mere plebs may think of them. Unfortunately, most of these devices are unsuitable as real health sensors - they are more just an alert that medical clinicians will use to initiate 'real' diagnostic monitoring and measurement. I agree with you that we need to ensure wearable IoT is more functional than fashionable but people's behaviour demonstrates it is likely the other way round. Perhaps we need to focus more on the M2M interactions?