Though many craftsmen may never ask themselves why it is they've selected their medium of choice (chair builders are content to provide furniture for seating, shipbuilders, to make seaworthy vessels), poets, and especially poets in America, are often haunted with the question, "Why the hell am I writing poetry when there are bills to pay?"
No one can sit on poems; no one can sail with poems, but the truth is poetry is a craft, no different from any other, and a worthy one at that. It may not result in the tangible product that many other pursuits do, but it does result in something.
Lowell's essay, "The Function of the Poet," provides an excellent answer to the "Why the hell..." question, and it explains the importance of the poetic result. It is a necessary read for any aspiring poet.
Russell's "The Function of the Poet"