Can't remove kwallet

The following lines manage to remove okular but not the kwallet. Why? rebuild happens without errors.

environment.plasma5.excludePackages = with pkgs.libsForQt5; [
    kwallet
    kwallet-pam
    kwalletmanager
    okular
];

The plasma nixos module differs between required packages and optional packages. Optional packages can be removed by the used pattern, the required can not be removed by that pattern if I se that correctly.

Ah, I see. That seems to answer it, yes. I feel like there should be some feedback to the user when attempting to remove a package which is marked as required, no? Seems like very bad UX.