Yes, and I confess to being one who used to think I'd never do the sports quantification.
I have a series 2 and have used a phone app called Cyclemeter years prior. That app became much more valuable with the watch. The app does several sports and a better job for specialty or specific sports than the native watch app. I use it for skiing and MTB and the native watch app for other biking. That's mostly so I can measure how much more or less my single track and skiing happen in a year.
There are reasons for a more specialized device but my day job - IT director - shows me how good the Apple scenario is on the whole.
Pros
Reliable whether hardware or app support. Easy to use. Benefits of a sports tracker with a whole lot of other nice features. Works with other measuring and tracking devices. Their "close the rings" concept is really good for overall lifestyle - especially if your day job is a desk job.
Cons
Sorry non-iPhone users. Some smart watches have the several days or week vs 1-2+ battery life. (Note: My daughter's series 3 might indeed get the better battery life advertised) Some products made mostly or exclusively for sports might be best for a subset of users.
No matter what my earlier use of heart rate monitors was unpleasant and a pain to work with the data vs Apple Watch. The watch is comfy and plenty good enough for my needs. I'm 58 years old and watching heart rate helped me get way better this year. I'm mostly a MTB rider or have taken that most seriously. I'm not a natural athlete. A good season used to mean I could lead the B group or slow pokes. I've moved up to eating the dust of the A group on some rides. If with fellow middle age and old farts there are times when I'm in the lead.
I'm way better at pacing myself on single track MTB rides. On Sunday I did a 3+ hour gravel ride 1/2 in a headwind. I was feeling fine an hour in but looking heart rate averaging 141 with 20 MPH wind in my face said back off. That made all the difference two hours later.
The nudge factor can really work for some people. We're not a jock or health club sort of family but all active and trim. My son who's been cautious or timid about physical activities has taken the close the ring idea seriously. He's become fit, strong and now indifferent to what peer pressure says. For me it helps me do more than bike, dig at trails and ski.
