That it supports fetching via Git as well as various via forge-specific tarballs, even for flakes, is pretty nice. It means that if your org uses Nix, you can fall back to distribution via Git as a solution that doesn't require you to stand up any new infra or tie you to any particular vendor, but once you get rolling it's an easy optimization to switch to downloading snapshots.

The most pain probably just becomes from the hugeness of Nixpkgs, but I remain an advocate for the huge monorepo of build recipes.