Why doesn't the create method return a DTO instead of just returning the id? Seems like that requires you to do explicitly do a read if you want the data for the object you just created.

In a high-performance situation (ex. large volume of creates) it's more efficient to allow the user to explicitly fetch the object values from the database via a read request, if those values are required. If the create always returned a DTO, it would in some cases suffer an undue performance hit.