What is the benefit of “Send Amazon Order Shipping Notification To Customer”?

What is the benefit of “Send Amazon Order Shipping Notification To Customer”?

Well, if you have regular updates about your order then you can easily get to know when your product will get delivered. 

Open the App  >  Click on Configuration  > Go to App settings 
By default,  "Yes" is selected so that customer will get shipping notifications from Amazon via email regarding their order status.