I'm not a giant fan of harry potter, but I have 4 kids...I buy collectors editions of any book I buy if it's available, just because I'm like that. So far, it's paid off. I've made over a grand from stephen king
Amazon.com: The Tales of Beedle the Bard, Collector's Edition (Offered Exclusively by Amazon): J. K. Rowling: Books
This is the coolest collector's edition of anything I've ever gotten, hands down.
That said, I'm not arguing music doesn't have information above 15khz, or that it's useful. I even used HF emphasized microphones to make my best recordings back when I used to do such things. Helped offset the rolloff distance caused.