Do mean Elastic Beanstalk? "EBS" is Elastic Block Storage, that doesn't make sense in this context.
Another thing to note, Elastic Beanstalk auto scales whereas you have to increase/decrease dynos yourself.
In other words, you may be paying for "dyno hours" (wall-clock time) when you don't need to.
It was mainly for throwaway projects. But you never know your throwaway project may start getting traction. And before you realize you may end up owing hundreds of dollars to Heroku.