Amazon's whole angle with Twitch is converting them into "new TV" for cable cutters (a huge, emerging demographic of young adults that will dominate the market in 10+ years). They've already been testing this stuff out with the likes of Bob Ross, Power Rangers, and Yu-Gi-Oh, which were all apparently successful experiments at this early stage of scale.
It's entirely possible that they make a new "division" of Twitch that they call something else as a more controlled Amazon entity with greater regulation/moderation as a function of their live TV initiative, advertised directly to mainstream consumers via Amazon Prime and the like. Thus, if that's the road they go down, Amazon will probably see a lot of success as an alternative to traditional TV with all your channels on one app.
We'll see. I don't think putting these events on the core Twitch platform is wise considering the user base, but Amazon is absolutely angling for profit off of iterations in the space. That is what got them to buy Twitch, not people cussing at video games in a corner webcam with donation messages scrolling over the top. With the right development, Twitch can be the Youtube of livestreaming in their eyes, which means big money from big media (musicians, shows, events, etc.).
"Alexa, turn on the NFL channel."