I agree that a single outlier is more stressful - but many times these aren't medical grade devices anyway so the actual data you're looking for is the trend (not the absolute values.
A solution could be to measure it but not really track / visualize it day to day.
I believe the value add is a combination of both factors - ability to measure and (as a consequence) induce more exercise.
An example here is how I made sure my parents are getting their exercise in by making completing their Move rings and 10K steps every day. This pushes them to take a walk in the evening instead of doom scrolling / watching TV.
Another example - Check trends like resting heart rate to see if my body has fully recovered from covid19, SP02 at night indicating potential sleep apnea etc.
The primary use for a smartwatch for myself (and many of my family, friends) is fitness and health tracking. Card payments, notifications, WatchFaces etc. are all secondary.
Basically what Whoop is doing with their strap - but minus the subscription model. I know a ton of people who tried the whoop but felt it was extremely pricey and didn't have the accuracy of an apple watch.
I would be happy to pay ~$400-500 up front for hardware that integrates with Apple Health and provides solid, reliable health tracking without a need for a subscription.
And by health/fitness - features expected would be sleep tracking, activity (gps), heart rate, Sp02, skin temperature sensors, fall detection. Then secondarily - additional things like ECG/EKG, apnea, AFib detection
The in-accuracy of some of the devices in the market is why I still choose to remain with my Apple Watch.