I agree with everything you said. I would just add that there is a 3rd possibility about why Kaiser Permanente (and lots of employers and insurance companies) are promoting these devices. I know of several major employers in my area that offer discounts on Apple Watches and incentives (either cash or deposits into a healthcare savings account) to employees that voluntarily participate in the company sponsored wellness program. However, the definition of "voluntary" is a little bit questionable in my opinion. In several cases, friends of mine told me that their insurance deductibles took a big jump at the same time their employer offered "free money" for joining the wellness program so a cynical person could interpret this as non-participants in the program are subsidizing the program for those who "volunteer" to participate.
The rules vary from employer to employer but some employers require employees to wear the watch nearly 24/7 and share their data (at least minutes of exercise, step count, and calories burned per day, but potentially even location, sleep patterns, heart rate, etc.) with their employer. While I love my Apple Watch, this is literally some of the most personal data I can imagine generating and I don't plan to voluntarily share it. I share some exercise related data on Strava and occasionally I will do an exercise challenge with a workout partner via our Apple Watches but I am not giving up resting heart rate, location and sleep patterns to an employer or insurance company.