Poe was definitely a great poet, and a master of suspense. He also had a serious obsession with writing about dead women. He did it in some of his other poems ("The Raven," "Lenore," "Ulalume,") and in his short stories ("The House of Usher," "Ligeia,"). In some ways, it makes a lot of sense, given his style. It's a subject that lets him tie together beauty, sadness, loneliness, the supernatural, and all his other favorite subjects. Of course those spooky, sad themes are also great calling cards for Poe.