Since this post was about a different book, on a 4-year-old thread, I have split it off. Please don’t add new questions to old thread.
You should consider the price difference as well as the cover difference. Beware: some “hard-cover” books are simply paperbacks with stiff covers. The real difference is that a true hardback has its pages folded and joined together by stitching through the fold. A paperback has its pages cut and glued together at the spine. The stitched method will last much much longer. Long enough to become dangerously out of date, in fact