1. I like having the same system configuration across machines and be sure that everything is the same.

2. I like having all configuration in one place and have comments near the relevant code for extra clarity.

3. Nixos makes setting up root on ZFS a breeze.

4. System as nix configuration makes it very easy to track changes with version control and informative commits.

5. If I fuck up the system I can easily boot into older generation.

6. System can rebuild only if everything (with proper checks) succeeds giving you a greater confidence in things working.

7. System reinstals are quick and easy so on hardware failure you can go back to work very quickly without having go spend days and weeks getting your system so vagualy similar state as before.

8. Nixos made it easy for me to set up mirrored boot so my system will still work fine when one of my boot drives fails.

9. I get to know what is actually installed on my devices and can easily get rid of it.

10. No dependency hell.

11. I can easily try out a program before installing it permanently with nix shell.

12. Impermanence helps me ensure that every folder and file that I need to keep is documented and keeps them in one place for very easy backups and I have 100% confidence at my backups have everything important.

And many other bigger and smaller things that I can't remember right now. I'd honestly be interested in solutions simpler than nix providing the same or greater benefits with more simplicity.

E: Also, because my original comment wasn't well worded I will mention that I meant that once you learn how to work with nixos things become easier and once you get the setup going it's just there continuing to work since the effort is paid in advance and you continue getting the benefits just like that.