What I don't understand yet, is what hardware on this band makes it different from other wristbands (besides form factor)? If all the calculations are done on t

What I don't understand yet, is what hardware on this band makes it different from other wristbands (besides form factor)? If all the calculations are done on the mobile app, and the wristband is just a data collector, why not implement this app to integrate with existing bands? We've seen so many wristbands (and now watches) releasing, it doesn't make sense to have separate bands for separate tasks. We'll eventually have a similar problem where every website has it's own app.