The health stuff on the Apple Watch is basically just for entertainment at this point. Which isn't to say it can't be useful, I definitely know people who have gotten more active because of the "gamification" of things like the activity rings.

If your watch reports say, a single atrial fibrillation event in any otherwise healthy individual, it doesn't do a whole lot for you. Even if you bring that information to your doctor, they can't be expected to do much with it. They could strap some additional monitors on you, but if it is a very rare event there isn't much chance of it recurring when they are actively looking at it. In some cases, the anxiety caused by worrying about it can actually cause more issues than just not knowing.

I actually like my watch a lot, but more for just a notification device/convenient payment interface rather than a health tracker.