Because you can (at least you can for a bit–they’ve been discontinued, don’t you know, so it’s all about stock on hand).
Of course, this also means you must be willing to actually lend your books . . . to other people . . . who may or may not know how to properly care for books. And let’s not forget the words of Anatole France: Never lend books, for no one ever returns them; the only books I have in my library are books that other folks have lent to me.
But, you know, your call.