Why are self-references actively prevented?

Self references are very valid relationships. What is the rationale of actively preventing them in awesomerelationship?

  $query->innerJoin('relationship_data', 'l', 'base.relationship_id = l.relationship_id');
  $query->innerJoin('relationship_data', 'r', 'base.relationship_id = r.relationship_id AND NOT (l.entity_type = r.entity_type AND l.entity_id = r.entity_id)');