I've been hearing a lot about it lately and I'm intrigued, but also utterly confused.

Is this a Linux distro I'd install on bare metal because it offers a new way of package management that addresses the issues other distros have?
Is it something I install in the distro I currently use?
How does it work and what does it do?

I've tried to read https://nixos.org/guides/how-nix-works but the first sentence is

"Nix is a purely functional package manager. This means that it treats packages like values in purely functional programming languages such as Haskell"

and that's where it lost me. Thanks for helping me understand!