As an Amazon Bestselling Author, you will have a much easier time getting into the media, getting booked and selling more copies of your work.
How many books will you sell?
This depends largely on the specific Amazon Bestseller strategy that you choose. It’s possible to become an Amazon Bestselling Author without even selling a single book (by using the Amazon KDP Select Free Promotion), as well as by selling tens of thousands of books by targeting paid lists. The choice is up to you. The main goal of this course is to teach you how to become an Amazon Bestselling Author and how to profit from this title in the long term. Selling your work should come second, after you are already an Amazon Bestselling Author.
To sum it up, being an Amazon Bestselling Author makes life much easier for you as a writer, because people will see that you have achieved a high status. And this will be the truth.