Yes for a solution for arbitrarily large networks cn=config could be
more scalable and cheaper. But that's not true for a small server for a
small organization that doesn't need the extra complexity.
I don't want to understate the pros of cn=config, I just state my
opinion about the cons. If you tell me the maintaining slapd.conf is too
costly in terms of developers energies I've nothing to say. But I don't
agree that cn=config is always better.