Nix is just one installer (I steer devs toward Determinate's installer) so technically not super-different from needing Docker. Lots of files in /nix but actually less disk use since the store has much more fine-grained de-duping than container images. Nix is still a big bite though, and for most projects I wouldn't make nix a requirement, but the project in question is itself a build system with reproducibility requirements in its design, so I'm not losing too much sleep over this one. The final artifacts don't depend on Nix anyway.