I am using the nix home-manager module for krewfile.
I have configured it as follows, but regardless of what value I set for krewRoot, the default "~/.krew" is always used.

programs.krewfile = {
  enable = true;
  krewPackage = pkgs.krew;
  krewRoot = "${config.home.homeDirectory}/.local/krew";
  upgrade = true;
  plugins = [
    "auth-proxy"
    "blame"
    "df-pv"
    # "insider"
    "ktop"
    "neat"
    "resource-capacity"
    "sniff"
  ];
};

To address this issue, I changed the KREW_ROOT variable inside the script so that it is read from an environment variable.