What is the purpose of chiasmus?

I think it has several connected purposes...

As a self confessed fan of chiasmus, I think it has several purposes:

• To give structure and poetic form, making text more digestible and memorable.

• To set the scene and draw the reader from where they are into the core, from the outer courts into the inner courts.

• To protect the essential core at the heart of the chiasmus and draw attention to it.