Remember that business about entities being super attributes? This is where it comes back into play. If I have an entity called news and another called article, both of which contain the same set of attributes, then they aren’t really two entities—they’re subtypes of a single entity type.
But now suppose that news and article have different workflows. Perhaps news items need to be approved by the director of communications, while articles need approval from the director of research. Since permissions are an attribute of content type, then these may need to be separate.
In my view, this is less an objection to my overall argument and more an additional point of evidence for the claim that content type and editorial function should be treated separately at the CMS level.
(Okay, technically, an entity is a sort of super attribute that contains a machine name, a human name, and some validation and permission rules. Again, this is important for developing a CMS, but not so important here.)