as the others have said price mostly. You are cutting out the middle man. Heroku has an awesome service, but they are just running on AWS. Elastic Beanstalk is basically the same Platform as a Service idea but you get rid of the middle man. I'm happy to see python supported as I was just getting started with a project and debating using heroku vs dealing with the hassle of doing it myself on aws. Now i get the best of both worlds.
