The way packages are like functions in the nix code repo gives you at least fair confidence that things will actually work as intended.
Or at the very least it gives you insight into why it doesn’t. More so compared to a traditional deb/rpm distro in my experience.
Not saying it’s perfect by any means, just that it has worked brilliant for a few small projects of mine involving some pi’s.
At the workplace though, resistance is high amongst my traditionalist RH/centos co-workers. :)
I recently had to change my work's notebook. Since my NixOS configuration was commited in my dotfiles, I simply restored my NixOS configuration and $HOME and everything was working like the old notebook.
Also, bugfix for strange behaviors are written in my NixOS files, so it is like NixOS is my own personal distro.