I use Linux at home but when I got my work MacBook I was able to get an identical setup (shell aliases, git config, shell plugins, nvim, etc etc) with very minimal effort and not needing to understand a macOS way of installing all these programs like with e.g. homebrew.

Declarative, reproducible, and no fiddling with macOS specific stuff.

Plus, we had instructions in our wiki for dealing with homebrew package installation failures and conflicts with macOS-installed versions of required software, needing to install other programs like Ruby version manager, etc to fix these issues. but with Nix I just setup a devshell and got the exact version we needed installed with no issues.

And this can be pinned and reproduced for every developer using Nix, eliminating the hassle for everyone.