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Lets see.
Apple Pay - I tend to avoid places that don't take Apple Pay - their loss.
HomeKey
Duo 2FA
Workout tracking - Workoutdoors and Strong
Music, audiobooks, podcasts
Messaging
Calls

Basically replacing my physical wallet and not having to need my phone for everything. It's so nice to go to the gym with just the watch and airpods and not have to need the phone to track.
 
Mostly:
- sleep tracking
- workout data

Less frequent:
- checking the time (!)
- taking phone calls truly hands-free (works extremely well but I feel like Dick Tracy)

Things I *don't* use if for:
- had to turn off fall detection. I was getting too many false alerts and it wasn't necessarily convenient to dismiss them, though necessary.
 
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