I wear my watch on the left wrist, and the Band on the right.
The watch mode is off and I use it strictly as fitness tracker and message monitor.
My watch, on-the-other-hand (no pun intended
tells time at a glance (analog). I can symbolically, at a quick glance, know how much time is left or what time it is without having to read and figure out from digital display. I realize one can get used to reading and figuring out time remaining or get an equivalent feel from glancing a digital numbers quickly, but I don't want to.
The other thing is my watch is a very thin metallic timepiece that can slide under a shirt sleeve on my wrist without any cumbersome attempt to tell time - unlike Band which is thick and bulky and does not fit under the shirt sleeve or jacket very well.