Does anyone write k8s manifests in raw yaml? They're so complicated that they're generated using some templating language (helm or kustomize or whatever is popular these days, I'm a little out of the loop). So you still have something programmatic. Think of Nix as just a better and more principled templating language. (I mean, look at NixOS configs: they're much closer to "plain structured files" than "programs".)
The promise that I see (I haven't seen this fully realized but it should be possible) is that instead of yaml plus some ad-hoc templating language plus dockerfile plus makefile, everything is in a single language top to bottom.
The promise that I see (I haven't seen this fully realized but it should be possible) is that instead of yaml plus some ad-hoc templating language plus dockerfile plus makefile, everything is in a single language top to bottom.