Surely there's a difference in usage. Apple's devices are specifically for personal information rather than for use by medical practitioners. I don't see a doctor/hospital using an Apple Watch for accurate diagnosis (especially in the USA), but I can see it alerting them to a possible problem that can then be checked (or enable them to focus resources away from unlikely issues). While improved accuracy is always good, there's a lot of benefit in broadening access to diagnostic healthcare devices as long as the user is aware of the limitations. Early detection and seeking medical attention can be critical.
In my home, I have many cheap DIY devices to test for damp, detect electrical circuits, measure temperatures remotely, test electrical continuity, check for water leaks, etc. as well as checking my heart rate when exercising etc. They certainly aren't good enough for professional use, but they do help me detect and correct problems before I need the professionals, tell me that I need to call someone in before the problem becomes too serious, or enable me to monitor ongoing issues. Most of them have similar caveats to the Apple Watch.
