Sometimes I feel like all I do is plug Nix. But NixOS has a neat feature where any (?) NixOS configuration can trivially instead be built as a "vm", which will

Sometimes I feel like all I do is plug Nix. But NixOS has a neat feature where any (?) NixOS configuration can trivially instead be built as a "vm", which will assemble an initrd for the described system along with a script which will run a tailored qemu invocation to launch the system, leaving a qcow2 file of any changes you make to the filesystem in your cwd. Makes the whole thing extremely usable, and is done in a very extensible way.