I am with you, I wouldn't wear one if they paid me. The data they are harvesting is a lot more valuable than the service they are providing.
I am sure health insurance companies are salivating at the opportunity to buy this data. Even if the data is anonymous.
I don't think there's much of an advantage to using a dumb phone. At least with a smartphone you can run apps that encrypt your communications.
By establishing a culture, where people are happy to share their data with the government anyone who isn't will automatically be a suspect. For example people who use TOR are put on a list. I don't know what live you lived, but some of my friends were under police surveillance (some police officer lived as a student for several years before his cover was blown by an acquaintance) because the government thought they had to keep taps on far left student organisations. Considering how much effort they went through to do that, I'm sure they monitor much more benign activity electronically.
That's a perfectly sensible thing to do. I would do the same thing. Any enlightened person would do it.