The argument against more monitoring is one of false positives. Suppose the Apple Watch has a 5% false positive rate, and detects problems with 1% of 100 million users.* That's 50k extra patients going to their doctors, thinking there might be something wrong with them. The next test may have a 1% false positive rate. That would put 500 extra patients on anti-coagulants.

That may not materially change the public health calculation, or it may. But that's the calculus -- not that a GP would blindly prescribe, just that increasing the top of the funnel is not necessarily a good thing. (Plus, extra cost.)

Positives and negative impact of additional testing must be measured for optimal decisions.

* numbers to make the math easy