Amazon announces subscriber numbers, but what do they actually mean?

Everyone who subscribes to Netflix is there for the video content. But that's not the case for Amazon--the majority of subscribers are in it for the free shipping--we still don't know how many people are watching 'Mozart in the Jungle' or 'Bosch.' Amazon has gotten awards buzz with the early seasons of 'Transparent,' and more recently, 'The Marvelous Mrs. Maisel,' but video is far from their main business. This is also why Amazon movies run in theaters, but Netflix movies largely do not--Netflix depends on people watching their content on Netflix. It's likely that Apple has been playing attention to Amazon as it also prepares to jump into the streaming game.