Yes, I use this same config snippet throughout my installs and haven’t gotten around to managing my home with Nix yet.
Later, I refactored this config snippet into a Flake that I include: https://github.com/stapelberg/nix/ …but that’s for a follow-up blog post :)
For git, you commented "for checking out github.com/stapelberg/configfiles". I wonder if you sometimes install NixOS locally from the installer? If so, I can understand having those packages around can be very useful.