The paperback release of a book is usually met with little fanfare. Coming a year or so after a initial hardcover, it's a chance to get a book in a lightweight, often cheaper form. Sometimes, the cover is refreshed. But authors don't usually host book parties for their paperbacks, go on special reading tours — or draw in readers twice. It is the same book, after all, only in a slightly different format.
Of course, "usual" doesn't apply when the author of the paperback is Prince Harry.
