what really excites me about this sort of initiative is the scientific possibilities that this data in anonymized form can provide.
With aggregates of this data containing all recorded dimensions (age, location, race, family history, weight, nationality, diet, etc. etc.) instead of having to perform decade long studies scientists could potentially test out hypothesis in seconds by running queries against an existing database.
IMO this could quite possibly be the most important thing we could do to accelerate scientific understanding of the causes of illness.