Some more points about Nix:

• It's a fast way to get to a specific setup, like a particular DE or Vulkan gaming support, thanks to abstraction that NixOS modules provide
• There are tons of packages
• Because packages are installed by adding a config entry you don't accumulate random software you forgot you installed
• Immutable updates and rollbacks - this is similar to benefits of atomic ostree distros, but the nix solutions are more general, so you have one system that does more things with a consistent interface
  • in addition to updating the base system, rollbacks also roll back user-installed packages, and configurations if those are managed via Nix
  • devshells provide per-directory packages and configuration using the same package repos as the host system, without needing to manage docker images
• Nix is portable - much of what it does on NixOS can also be used in other distros, or even on Macos or Windows with the Linux subsystem
  • Configurations often combine NixOS and Home Manager parts. The Home Manager part can be used à la carte on other OSes is a way that is fully isolated from the host OS package management. For example on Macos this is a much nicer alternative to Homebrew.
  • devshells also work on other OSes
• similar to Guix - but NixOS uses systemd, and is (from what I understand) more tolerant of non-free software (whether these are pros or cons is up to individual interpretation)