Graphic novels

I'm intrigued by librarians fascination with graphic novels. There's something happen in libraries that isn't happening in book shops. Booksellers I'm talking to say their graphic novels sections are growing - slowly - and I suspect many of the customers buying graphic novels from booksellers are school and public librarians. Clearly kids are borrowing graphic novels from the library or reading them there, but they're not buying them in bookshops. The books kids are buying are old-fashioned long form narratives. A conundrum.