Angular UI will only make assumptions based on link names/ids (and not based on URLs). It will then proceed to grab the link URL (href) from the REST API (via HAL format).
This provides flexibility in the REST API layer (allows links to change URL structure, as long as name/id does not)
Also potentially helps support plugins/addons and/or configuration. If a plugin/addon/configuration enables or disables an endpoint, the Angular UI can respond accordingly to either display or hide the component associated with that endpoint.
NOTE: This same concept needs to occur at all levels of requests (not just the homepage/top level endpoints). That was part of the reason behind the ticket:https://github.com/DSpace/dspace-angular/pull/127