We do not (currently) consider other ID types as 'end points' justifying to create an override hierarchy, however if the 'root' ID (i.e. the ID the user selected as base to create the override) is not an object or collection, we still want to check all of its dependencies. This fixes e.g. if a material depends on another Empty object, and user tries to hierarchy-override that material, its Empty dependency not being overridden.