The primary benefit of practicing any art, whether well or badly, is that it enables one’s soul to grow.

Kurt Vonnegut, Jr. (1922–2007) American novelist, journalist

“Despite Tough Guys, Life Is Not the Only School for Real Novelists,” New York Times (1999-05-24)
    (Source)

Part of the Times "Writers on Writing" series.

In Man Without a Country, ch. 3 "Here Is a Lesson in Creative Writing" (2005), Vonnegut expanded on this:

Practicing an art, no matter how well or badly, is a way to make your soul grow, for heaven's sake. Sing in the shower. Dance to the radio. Tell stories. Write a poem to a friend, even a lousy poem. Do it as well as you possibly can. You will get an enormous reward. You will have created something.