Do you think that when the Egyptians were creating hieroglyphics and paintings, there were people standing around saying, "I don't know why you're spending time doing that. You're not going to get a real job"?
Or when the Greeks were building the Parthenon, they did that just to kill some time because they didn't have anything "better" to do?
Or when Michelangelo was painting the Sistine Chapel, his patrons said, "Well, you need something to do, so you can paint on the ceiling - just don't make a mess"?
How did we get to the point where we feel like we have to justify the arts? People write whole white papers on how music improves math skills because they are trying to justify music in the context of what society seems to "really" value. Things that will get you a "real job."
There's also this idea that the arts are only for people who have "talent." As if making marks and storytelling and moving a pencil around is only good for certain people, those who are going to turn this activity into something "real." Everyone else needs to go get good at pushing paper.
We don't tell people that if they are not Mark Twain they should not write. We know that writing and the expression that it enables is important to being a person.
People with talents benefit society. Really good mathematicians and surgeons and athletes and filmmakers and writers and plumbers and singers and firefighters and public speakers are people we value.
But we've got to stop trying to justify the arts in the context of something else, like reading or math or commerce. Art is how we speak the truth about being human. When we look at ancient civilizations, we look at their art to understand how they saw the world fitting together.
Art isn't something else. It's art. Period.