Poetry brings out that creative side of a lot of people, allowing them to express themselves through a complex (or simple) structure of words. If we had no poetry, a lot of people would suffer. Prose writing would vanish, tearing out the hearts of writers everywhere, as it is such a beloved form of writing to so many people. Music would lose a lot of choral pieces. A lot. Speeches with a very poetic form - like "I Have a Dream" by Martin Luther King Jr. - would lose much of their effectiveness due to their loss of flowing rhythm and structure. Like I said before, a world without poetry would not be nearly as exciting and well-off.
Poetry adds so much to the world. It gives us a piece of life that helps us transform into more creative thinkers and build up our character, making us more well-rounded people overall. Of course, some people hate poetry or at least certain elements of poetry, and that's fine. It isn't something everyone has to like. Personally, I like poems with a very musical or flowing feel to them. I hate poems that are intricate and so filled with complex symbolism that I can't tell one word from the other. In all honesty, a LOT of poems are like that. But every once in a while, you get a nice, simple, and down-to-earth piece of poetry that just lifts your soul. You know what what I mean? After all, poems are usually created for the audience - whether that be to prove a point, or to simply evoke an experience in the readers themselves.
Poems are used for enjoyment, for learning, for gaining techniques like memorization and applying those techniques to other elements in life, for writing, for music, to prove points, and to boost people's everyday moral. In my opinion, poetry has thoroughly embedded itself into the everyday life of people worldwide. Poetry is something in life that just clicks, and it will grow even larger before you know it!