On that topic, I would have liked a new AirPods Pro to be able to monitor my body temperature through my ears, while I'm working out.

It would be nice to have constant monitoring against a baseline as well, to alert people when a fever might be breaking out.

If they are producing and selling it on amazon means someone buying it even if you don't need it. Body temperature check definitely would be handy. Those sensors definitely don't cost $20-30. I had CC1350 SensorTag and it already had that for retail price also around ~$35 (but altogether with 10 different sensors inside and that bought 10 years ago).

They also sell smart outlets, back massagers, and garden sprinklers on Amazon. That doesn't imply people would find them handy in their phone.

I think it'd be an easier pitch in the watch though as that's where they are already shoving most of the health sensors (and have wrist temperature monitoring already).

I read that first part in 2007 Steve Ballmer's voice.

You can also read it in 2015 Tim Cook's 3D touch announcement voice or Zu announcing the ZTE device with a 3D screen in 2017 or whoever at LG announced the wide angle lens, got meh to bad reviews about it, and then it took off afterward anyways.

My point here is I'm not saying it can't ever be something anyone would want because of that rather something selling in another device on Amazon has no weight one way or the other on whether it'd be a good thing to add to a phone.

There's lots of devices that can do all sorts of things, but not needing a separate device was their point