Nobody except Asia buys watches anymore.
Watches, smartwatches, health monitors - if you're not actively sick, they tend to be a bad idea.
Research studies have shown smartwatches actually encourage you to self-defeat health and exercise goals, by setting an upper limit on how much you do. Better methods include bar measures (where you start off in Red, go to Yellow, go to Green, and then go Yellow if you exercise too long without water or a rest break), candy systems (e.g. Pokemon Go where you get candy for your monsters if you complete a designated unit, but it doesn't stop adding), and other real feedback cycles.
Also, self-monitoring tends to decrease the reward aspect of the exercise itself.
Plus, seriously, who spends $500 on a fricking wristband?