Congrats on your purchase, hopefully you're settling in and enjoying the new watch!
I haven't worn a traditional watch since 2017 when I got my Apple Watch. I like the haptic feedback of the notifications on my wrist. There are times when my phone is on vibrate/silent and in my pocket, or on my desk and I'd never know someone was calling, texting, emailing, etc. Flight changes and Uber are also types of notifications where the haptic feedback stands out in my mind as being helpful. Alarms too. I can set my alarm from my phone and get haptic feedback on the wrist. Phone can be in another room, or you can set it from your watch.
Health in general. I've used it for sleep tracking, to help promote physical fitness, and archive that data which I can review and act on. When I'm walking or biking, I can look down at my wrist to see my progress. Of course it also tells time

And on the note of Health, I've found HealthView a better alternative to Apple's Health. HealthView gives a significantly improved way of viewing the various types of health data that Apple Watch can capture.
The apps I use most off the top of my head are in no particular order:
Cyclemeter
Bose SoundTouch--control volume and presets
Carrot Weather
Breathe
Workout
SleepWatch
AutoSleep & HeartWatch
Can be used with camera apps as a remote to snap a photo
UConnect to start/stop lock/unlock my vehicle
Home to power on/off devices
Apple Pay
Stand Reminders--I work at home and work at my desk, so being mindful of standing and moving is great.