The scope of this project is insane. Apple isn’t starting small with this one. Although it is currently unknown where Healthbook sources this vast array of data from, I have to think it’s an Apple wearable. Apple is a selfish company; they only spend significant effort on stuff that directly benefits themselves. Healthbook will only be useful if it gets a constant stream of reliable data backing it — the only way for Apple to guarantee that is by making a device it controls.