Why and when is katello-host-tools required in Satellite hosts?

Issue

• The Satellite Managing Hosts document states that either katello-agent or katello-host-tools are required in the Satellite registered hosts.
• Modern versions of subscription-manager have the ability to upload the profiles of installed packages and enabled repositories.
• Why is katello-host-tools required if my Satellite host runs a version of subscription-manager that already can update these profiles?