I am in the process of publishing what will be my first book. It is a Novella. Many writers shun such work as being too short to tell a proper story. They can’t make enough off these books. I have heard a million reasons. The part I keep coming back to for myself is the growth of the story and characters as it continues. If I were writing a one off story I would agree that it was too short. The series aspect gives me room to introduce the main characters, chart the growth, and give some back story without ruining an otherwise perfectly good book with countless flashbacks. Flashbacks are fun for the author but tedious to readers. often the reader gets confused enough to set the book down. You never want them to put the book down until it is done. If you have a different opinion on this subject I would love to hear it.