deleted rejected, deleted, permanent rejected map are good as they free up the valuable space and ensure moderation much smoother.
for example would be multiple upload. when we physically delete those multiple upload and give user a fresh start, we could 100% ensure the user only upload it once. if we see any deleted or rejected map in the future by the user, then we knew he was multiple upload.
previously when the rules had been updated and the map was deleted (not physically deleted), it was painful for me to mod it as i gotta be sure the deleted map was purge and not multiple upload by the users.