It is fiction. It is compact and tight. It contains all of the same elements as a novel. It can be discussed in a few classes. Students can read many short stories in the same time they might need to read a novel.
Students can also write their own short stories.
I began teaching English in 1974 at prep schools in New England. For the past 13 years, I have been teaching in a New York City public high school. For ten of those years I have had computers on all of my students' desks. This last year, each computer has been connected to the Internet. This year, after teaching English for more than 20 years, I have been more excited about teaching than I was when I first started.