It’s often compared to “Twilight,” which was also dreadfully written (I assume — all I read was the bit on Amazon). I suspect the appeal is of the same kind — the idea that a woefully ordinary woman can attract a terribly powerful and/or rich man.
Mills and Boone has made millions on that premise, however a lot of the people who’re rabid about Twilight or 50 Shades of Grey like to seem themselves as superior to the average romance reader.
I didn’t even bother with ‘Twilight’.....Bram Stoker’s work is magnificent enough