An interesting piece on Medium entitled What is the Purpose of Poetry? https://medium.com/the-howling-owl/what-is-the-purpose-of-poetry-147ba89ef9b0.
For me, poetry is valuable in and of itself. As with love and friendship it matters because it matters. If you where to pin me down and insist that I provide a fuller explanation, then I would say that poetry matters because it stirs the emotions. It speaks to who we are/explores what it is to be human.
As an aside, I am often puzzled by those who derive great pleasure from pop music (which almost invariably rhymes), yet dislike poetry, much of which rhymes! Perhaps the dislike by some of poetry stems from them having it drummed into them at a tender age rather than having discovered it for themselves.
My love of poetry was sparked by a school teacher, Mr Delacruz who recorded several cassettes for me, including a number of poems. In addition, I spent many hours in the school library discovering poetry for myself via anthologies such as Palgrave’s Golden Treasury and the Oxford Book of English Verse.
As always, I would be interested to hear your views regarding the purpose of poetry/what poetry means to you.
K Morris - Poet 
Thanks to your teacher, Kevin! I was never exposed to poetry at school. Don’t ask me why. xx Michael
I remain grateful to this day to Mr Delacruz, and to my grandfather who read on an almost daily basis to me. I’m sorry that you had no exposure to poetry whilst at school. I think poetry enriches all our lives.
My initial thought is that poetry doesn’t need to be defended as having a purpose.
I agree with you, Liz. As with love and friendship, poetry is valuable in and of itself and does not have to be defended as having a purpose.