Earlier quoted context omitted.
Because it's ultimately not very useful. Sleep tracking - I've become convinced this is actually a bad idea, and since I stopped I stress less about sleep and ultimately sleep better. Step tracking? Phone does that adequately. I do wear it for workouts, but once it's closer to end of life will replace it with something dedicated for workouts like a Garmin that holds a charge for 14+ days.
I’ll add that if you care about working out with a watch to track heart rate, the Apple Watch is pretty dismal. I moved to pairing mine with a Polar H10 strap so that I could get much faster feedback on heart rate recovery post sprint. In addition to using an optical sensor, the Apple Watch may also be doing something to smooth out the signal. I just know that the Polar seems much more responsive and matches how I am…
Check out the Quantified Scientist on YouTube, he does some interesting testing on health devices.