Yes, exactly!
With no content storage and 100% streaming, there's no reason this couldn't work from any iDevice to any AppleTV. What I mean is: Say you have the MLB app on your iPhone, but your friend doesn't but he has an AppleTV and giant screen. You go over there with your iPhone, tap a single button, and you can both enjoy the game on the big screen. There's no syncing or sharing of iTunes accounts necessary. The same for sharing and enjoying movies and TV shows with friends. This is exactly the element that's missing in almost all current online content delivery schemes.
The great thing would be that you have video on-the-go all the time, and you now have the additional option of viewing it on a bigger screen at home. It'll be hard for content providers to say, we're providing the video to users on the iPhone but we don't want them to have the ability to see it on their TV.
*Memes not required for API compatibility.