The "String Quartet" of American Idiot features renditions of the complete album replacing the sound of full electric guitars and solid drums with the violin, viola, cello and double bass. I can't imagine a more niche audience for target audience, Green Day fans who also enjoy stringed arrangements? I don't doubt there's an audience for it, and after having the chance to listen to it, I don't think it'll disappoint those who already have a taste for the style.