Yes but « docker build » already exists and can already be made deterministic so it’s indeed somewhat competing. Would anything be easier by using Nix?

Right now it seems to me like a large ordeal with little to no benefits and my interaction with the Nix community hasn’t been very convincing. A lot of Nix users seem to believe determinism and reproducibility of everything to be enough of a justification in itself. I don’t think it’s worth the pain.