Was excited about this until I saw that it doesn't support Amazon Prime video.
That app works with Android TV devices, too, although there's an issue there that trips some people up. When it first launches, it will look for Chromecast devices specifically but will not pick up Android TV ones. Even so, if you thereafter select the "Cast Screen" option, your Android TV devices should show up, as my Nexus Player does.
1: https://play.google.com/store/apps/details?id=com.google.and...
What sucks is that the real losers in all this are the customers.