Primary Purpose

a great poem generates a need to be remembered

a desire to make others read it out loud too
and revel in the clever word choices it makes

choices that appear as immutable as the notes
in a Mozart symphony, though the author
may have penciled and erased them dozens of times.

all else:

whether it shows or tells some larger truth
or celebrates the seasons of love
or counts thing one and thing two...

all else is secondary

Author notes: https://allpoetry.com/contest/2813591-What-is-the-one-thing-that-makes-a-poem-wor