If I lived with any family, making non-sudoer accounts for them on at least some of the machines would seem like a pretty normal thing.

I could use a cheap throwaway laptop, but actually using my M1 MacBook saved me. One time I was running a slideshow that lead into a new years countdown, somebody decided the laptop was in their way so they unplugged the power cable and moved it. It ran on battery for 6-7 hours before I noticed and nearly had a panic attack.

For your bonus question: I run GrapheneOS and as of now I have 8 user accounts. This might be a bit much for most people. The idea is that my main personal and work accounts use exclusively open source apps, and any context which demands proprietary apps gets siloed off somewhere. Two of the user accounts have google services framework installed, but neither is logged in to the play store.

The reason that the phone is more complex is that I am essentially never forced to use proprietary apps on my desktops, there has always been a way to work around it. But not so on the phone.

Things get a little fuzzier on Linux machines where there is both my user and a an admin "user". I treat the other as an abstraction, and type "sudo" if it won't let me do something without invoking that. Sometimes there are problems where I need to install something with sudo, then can't access it as my normal user and vice versa.

Sure, I could boot into single user mode (can you still even do that on a Mac?) but it’s a pain.