I am deeply skeptical that anything other than R&D and patents will come out of this move by Apple. I am bearish on the prospects of using technology in healthcare. Primarily for these reasons:
1. Regulation: it is very hard to innovate at the pace of the consumer-electronics industry while satisfying FDA regulations.
2. For general purpose applications, signals and measurements are highly noisy and sensors are still deeply in the academic realm, working only in very special use-cases, as opposed to 'in the wild'. It is a different matter for special applications such as Type-I diabetes or other diseases because devices are critically important and patients are willing to tolerate discomfort (of wearing probes, pumps, etc.)
3. In general, predictive power of algorithms tends to be lower for non-genomic health care applications because of variability across individuals, errors in installing devices, rarity of certain types of data for training and validation, etc.
4. Some of the key benefits are hard to grasp for users because of the slow time scales over which things like weight loss occur, and also due to the multi-factorial/multi-component nature of human well-being.