Of course, this is a sort of a (deliberately) ridiculous question. People who love art understand that works of art aren't "for" anything - they exists for their own sake and on their own terms.
People who don't see the value of the arts will dismiss works of art as "pointless" or "frivolous" when confronted with something that is outside their comfort zone.
However, when you look closely, I think it's clear that works of art have their own "thing" happening. They're not like a hammer or a washing machine or antibiotics, which were all created for utilitarian purposes.
And yet.
Did you hear the story of the Iranian Canadian journalist who was tortured in an Iranian prison. I heard him on the radio while driving between Fredericton and Moncton, and it hit me like a ton of bricks.
Here's what he recounts:
Bahari said he felt the walls were closing in around him while in solitary confinement, but he was comforted as he hummed the words to Leonard Cohen's song, Sisters of Mercy. He said the title came to him in a dream about two women who both looked like his sister.
"And all of a sudden this universe was created, this universe that was guarded by Mr. Leonard Cohen, and it was just ridiculous to me that this old Jewish [man], and one of the most cynical poet songwriters in the world, managed to save me in the heart of the Islamic Republic."
How would Leonard Cohen have ever known when he wrote that song that someday it would be a lifeline for someone being tortured in prison? There is no way to know that as an artist. And yet, by creating something with it's own meaning (ie. the song), in making a little 'world' in there, it went into the journalist's memory (somehow!) and stayed in there until it was really needed by him. And then, it reappeared when linked to the memory of his sister.
No part of the logical brain - no report, no spreadsheet, no strategic plan, no schedule, could ever provide this kind of sustenance at a moment like that.
And so, I think that's partly what works of art are "for" - to take on a life of their own, aside from the author and to go out into the world and become a part of some of the people who encounter them. To speak the heart, to be non-rational and yet significant.