[dbcurtis]

Not entirely true. My wife has O2 respiratory efficiency problems, and uses both an Apple watch and an Oura ring for sleep monitoring and charts O2 patterns daily. So at least some people care intensely. As to sentence two, it was exactly the O2 feature that prompted my wife to get the watch. No O2 monitoring, no sale. If O2 monitoring went away on her current watch, the watch would be up on E-Bay, most likely, as she doesn't find anything else about it that compelling. In my case, the compelling feature for me is exercise tracking and heart-rate monitoring.

This is yet another case where it is easy to fall into the "product manager trap" -- that is: designing for "most people". The trap is to de-feature things where "most people" have only modest engagement, but a few (likely your most evangelical customers) care intensely about that feature. Don't fall into that trap. The goal is to create a feature collection of "the one thing" that each segment cares intensely about, not to create a basket of meh features that everyone finds meh.