It creates an easier way to understand how a piece of writing or in your case a poem is built up. For example if I was writing a poem I would need to think about how I could build up the poem and what I could add to it at different times of the poem. Therefore when in a poem it could be helpful because it would help us understand how to build up a poem with levels of structure meaning adding up more stuff at different bits of the poem I waffled a lot but that’s a brief answer hope it helps x :)