Not sure if you live in the US but my experience with the US healthcare system (I work adjacent to one of the top US research hospitals) is that there is a critical problem of patient identification between institutions. Because we have no national ID system, patient data is coded for individual institutions (with some limited exceptions). So, transporting your medical data between institutions is a headache that can result in lost information. Further, access to this information for your own knowledge, research or simple interest is quite limited if you don't have a healthcare provider using one of these established secure platforms Apple Health can pull from.