What's "Multi user?" and why should I know about it?

[Alper Cugun]

This looks like a fairly important distinction:

The word "root" does not appear anywhere else on the page. No idea why it's there or what it's telling me.

[Ian Burzynski]

I assume here "root only" refers to what is called "single-user" installation in the Nix manual: https://nixos.org/manual/nix/stable/installation/installation.html

That page in the manual briefly mentions the difference between the two. There is more information in the Security section, on these pages:

https://nixos.org/manual/nix/stable/installation/nix-security.html
https://nixos.org/manual/nix/stable/installation/single-user.html
https://nixos.org/manual/nix/stable/installation/multi-user.html

Per the manual:

We recommend the multi-user install if it supports your platform and you can authenticate with sudo.

[Alper Cugun]

Ah ok. I wouldn't rely on off page documentation because in the nix ecosystem a lot of it is lacking and/or outdated. A brief note here about the difference would be better.