https://www.theatlantic.com/entertainment/archive/2013/11/what-is-a-poem/281835/
Extract:
There is at least one kind of utility that a poem can embody: ambiguity. Ambiguity is not what school or society wants to instill. You don’t want an ambiguous answer as to which side of the road you should drive on, or whether or not pilots should put down the flaps before take-off. That said, day-to-day living—unlike sentence-to-sentence reading—is filled with ambiguity: Does she love me enough to marry? Should I have sex with him one more time before I dump him?
But such observations still don’t tell us much about what a poem really is. Try crowd-sourcing for an answer. If you search Wikipedia for “poem,” it redirects to “poetry”: “a form of literary art which uses aesthetic and rhythmic qualities of language—such as phonoaesthetics, sound symbolism, etc.” Fine English-professor speak, but it belies the origins of the word. “Poem” comes from the Greek poíēma, meaning a “thing made,” and a poet is defined in ancient terms as “a maker of things.” So if a poem is a thing made, what kind of thing is it?
How my heart sings 
I like the idea of poetry as literary art. If one can express ideas using poetic form, that’s great, but free form is good too. I think it is more necessary to get the message across rather than getting it gnarled up because one is trying to fit it into a form.