Cant purchase Kindle books or movies with app

Whats the point of having an app for a store when many of things that the store offers arent available for purchase "through the app." If I want to buy a movie, I have to close the app, switch to a browser, log in, and purchase the movie. Same phone, same network, but many times the effort. Same thing with Kindle books.

eeedge about Amazon Shopping, v9.14.0