I have a Garmin Fenix 5 Plus. I track my activities whether it's a long walk, a hike, or paddle. It helps when hiking because if I get a bit lost, I can look at the map to see the trails I've walked, or how fast I've paddled/hiked/etc. It also has an emergency function so if my heart rate suddenly spikes or if I quickly drop in height (like a cliff, though it has been triggered once when I climbed down a water fall), it'll send an emergency message to my emergency contacts with coordinates.

I have it set to remind me to move every hour if I haven't moved from my desk. This in addition to step counts.

Sleep tracking, though Garmin is/was notorious for poor sleep tracking, so I don't really count on it too much.

Date and time. I also have a little clock on the bottom to tell me what time it is back home so I know when to not call.

I like seeing my fitness go up on the dial. Not so much the other way around.

I also use it for my morning wake up alarm. It vibrates on my wrist instead of an audible alarm to wake up the +1. He doesn't have a smart watch, so I wake up every morning at stupid o'clock.

Badges. I love collecting the badges.