IMHO it's a matter of "data cleaness" to prevent human mistakes. The most common case is an apparent  one-to-one relationshio between works and editions, but there is an underlying one-to-many relationship; from my small experience about database good rules, invariably problems pop up when database structure is designed for "simpler case" as soon as a previous one-to-one relationship turns into a one-to-many one (in our case, when a second edition must be added to the first one).