I have a few points for you in response:
1. I'm what you'd call a "watch guy." In the time I have had the Apple Watch Series 2, I have barely used my mechanicals (including a Lange & Sohne and a Nomos Glashutte). The Apple Watch comes with me on all but the most formal/elegant occasions, and I now hate changing straps on my mechanical watches in comparison. The Apple Watch may not be as beautiful, but it is far more versatile and useful. When I want to dress it up a bit, I throw a Hermes leather strap on it, which works nicely in just about everything other than a suit (which is essentially the only time I'd jump back to the Lange).
2. You're vastly underestimating the utility of quick replies on the Apple Watch, in particular. I have quick replies for every conceivable response I could give to someone that is fewer than five words or so. This makes a lot of communication much faster because I don't need to take out my phone - I can tap, "congratulations", "cool!", "no", "yes", "I'm in a meeting", "I'm in a movie", etc.
3. Having notifications or synced functionality on the watch is a very frictionless way of enhancing iPhone interaction. As other commenters have said I can quickly glance at a multitude of things, not just the time. If I receive a message on Slack, I don't need to take my phone out if it's not something that requires my attention. When driving, I can have directions on my wrist directly, instead of on my dashboard. I can even have conversations on my wrist, hands free, while cooking. These are all ways it's directly enhanced my life in ways I wouldn't have really thought of without trying it.
4. I run a fair amount - at least 30 miles each week. The Apple Watch is the single most empowering device I've ever had for quantified self tracking and fitness enhancement. Having a pair of Airpods and an Apple Watch is a fantastic combination - I can't even imagine bringing my phone with my on a run anymore. I can look at my wrist to see my pace and split information, and that's just on the native Workout app. I can track my heart rate constantly using something like Cardiogram. I can also track my sleep. There is a massive amount of data enablement that I can now see and monitor as much as I want in the Health app.