This article from the Huffington Post says it all - music doesn't need to be a tool for other kinds of learning. It's quite enough all on its own - a lifetime study well worthy of our effort.

Stop "Defending" Music Education by Peter Greene -- Huffington Post June 24, 2015 

"Today I ran across one more xeroxed handout touting the test-taking benefits of music education, defending music as a great tool for raising test scores and making students smarter. It was just one more example among many of the "keep music because it helps with other things" pieces out there.

"I really wish people would stop "defending" music education like this." (More...)