The best I can tell is that the Health app is more of a hub to see aggregated (raw-ish) data, and set/update permissions on what apps have access to what data.
I don't think their intent is to compete with any of the apps out there that use the data though.
I believe your correct. The iPhone 5s, 6, and 6+ all record the number of steps you take thanks to the M7 motion processor, but that seems to be more of a 'because it's there' thing.
> Why would Apple publish the app at all?
Because the intention was to have third-party apsp and device integration at launch. But something went wrong, and all the partner apps were pulled if already published, or postponed if not.
Re:How to see your iOS8 health data
by coolfilmaker on Sunday September 28, 2014 @07:17AM
(#8379448)
It's called HealthKit because it's basically a software development kit. The GUI is clearly more of an afterthought and a way to keep the settings from getting buried in the already packed settings app.
It seems like they should have released iOS8 with some kind of simple pedometer/stair counting app that looked good and was easy to use, like a reference application to show what HealthKit could be used for, and then buried the HealthKit app as it currently stands in some settings menu that most people will never need to look at.
The only thing I can imagine is that they intended to roll out a bunch of HealthKit-compatible apps from third parties like Nike and FitBit along with iOS8, but the bug messed up their release plan.