The problem with asking about the rationale behind a single entity is that it's not likely to be documented enough to be answerable by someone else than the original designers.
Also, some may recall there used to be a close reason for asking a question that is "too localized". These questions are not likely to be answerable and useful to others. This question falls into the "too localized" category as far as I'm concerned.
I think it would be on-topic (and more likely answerable) if the question asked about a body of works instead of a single one.
For example, this question has some similarities but is applicable to multiple instances in a common field and is well documented.
I'm pretty sure asking "Why are most poetry works typically laid out with sober type and a lot of white space?" would yield interesting and useful answers.
Other related questions:
Why is Courier the preferred font in the legal industry?