and you know that it ca work on other watches how?
and yes, it does work on S9 and on Ultra 2, both have the S9 chip which got neural cores last year, previous AW chips didn't have that
That's all well and good, and aligns with Apple's marketing.
But teardown show that there's been no additional sensors added between Series 8 and Series 9, and none of those found in Series 8 have been upgraded in Series 9.
And if you really read the official comparison charts and Apple's marketing of Series 9, you'd see that Apple doesn't even claim that sensors have been added or upgraded.
And just to be very clear, the SiP 9 is "just" a faster and more efficient at everything than Series 8. But
the SiP has no physical sensors in it. The SiP "only" handles the data input from sensors, like the gyroscope, heart-rate sensor, etc.
With a little critical thinking, and considering that Series 8 is doing 1/1 the same fall-detection, sleep tracking, automatic biking and running and walking detection, swimming detection, Crash Detection, etc., as Series 9 is capable of, you just might be able to acknowledge that Sleep Apnea detection is a software-based algorithm that Series 8 could do but won't because Apple needs more reasons to get buyers to upgrade.
Yes, Apple can arbitrarily block any feature from older models that they want. It's their product and their (insanely profitable) business model for Watch.
But I will not listen to this nonsense of Apple upgrading Watch with every new SiP generation. It's just not happening.
And why would it?
-Apple has absolutely dominated the smartwatch/fitness tracker market for over a decade and barely has any competition.
No company in their right mind throws any substantial r&d at their products if consumers buy the newest generation regardless of whether anything substantial has changed or not.
Apple only makes an effort in product categories where there's substantial competition. Watch is not that.
Look no further than the actual specs of Series 10, the very few upgrades (really just the display and chassis), and then look at how Apple wants us to think of it as a complete overhaul.