You can change that in system settings on KDE

System settings -> Software Update -> Apply system updates immediately

Not sure if it’s the same on GNOME

It’s like talking to an American who keeps asserting they don’t have an accent. If they don’t get it immediately, they’re probably not going to.

It only makes sense to you because you’re accustomed to it, not because it’s innately better at “gauging human comfort”. All of us who grew up using metric know how to gauge comfort with Celsius. None of us bother with decimal fractions of a degree because there isn’t a big enough difference between degrees to do so, so your argument about granularity falls apart pretty quick there. You lot don’t have trouble with miles despite kilometres being more granular do you?

They’ll definitely know. Microsoft’s last update for Windows 10 will make sure to add as many notices, popups and scary alerts as possible.

And as a result plenty will care, particularly those who aren’t tech savvy. If you’ve got relatives for whom you are their go-to IT person, be prepared.