For me NixOS is not about recovery. It's about reproducibility and purity, where you can try any available software in the nix-shell and remove it easily without garbage left behind. This is a real superpower. Windows and MacOS will never be able to achieve it.
And I run rsync on my home directory to my local file server.
That's really all I need to recover. But I don't think I have had to recover a system in a very, very long time.