I think disgusting is a bit harsh here. You'll find other self-updating software in nixpkgs already, like Steam. I don't think it's reasonable to expect all software to conform perfectly, and one of NixOS's advantages is that it can still find a place for that software to fit in. Ultimately whether to include this or not should be a question of practicality, and not some ideal of purity. The question is whether we inconvenience people by making them add an unofficial overlay, or give them the convenience of an official package in nixpkgs. I would prefer the latter.