Apple Watch features I find handy:
1) Single lead cardiogram
2) Heart rate sensor
3) Walkie-talkie
4) Answer phone calls from your wrist
5) Find your phone easily

6) Tells the time, okay, a $12 watch does that
7) Large print date and day (that's a huge thing for me personally)
8) Turn by turn navigation when driving or walking
9) Taps my wrist when it needs attention (I tend not to keep my phone in my pocket)
10) Pay at the register or subway without taking my phone out
11) Pay at the register or subway when I forgot my phone (and wallet)
12) Timers - phone's clunky for that
Body fat estimations tend to be grossly wrong on scales and such, I doubt Samsung has figured out how to do it accurately from your wrist.