https://docs.redhat.com/en/documentation/red_hat_satellite/6.16/html-single/installing_capsule_server/index#configuring-capsule-for-host-registration-and-provisioning_capsule suggests its procedure is required in case one wants to register (or proviion) clients via a Capsule.

For registration of clients itself, the section is completely wrong. (RHSM) Registration per se works well against default installed Capsule. The only piece not "working" is that client behind Capsule does not a direct way to request Satellite for generating registration command (Satellite's `api/registration_commands` endpoint). But the procedure in this section does not change this - it alters Satellite config "only", while exposing the API endpoint to Capsule would require a change on Capsule.

So I dont understand the reference to "registration" in the section. It is rather misleading than helping.