Upstream has this alias too; so that dbus activation works. What I don't fully understand is why this would ever be useful given this unit is already started way in early boot; even before dbus is up. But lets just keep behaviour similar to upstream and then ask these questions to upstream.
*** NixOS *** NixOS is a Linux distribution based on the purely functional package management system Nix. More information can be found at https://nixos.org/nixos and in the manual in doc/manual.