In case you missed it. New Chromecast (Nexux Phones and Google Tablet) on the way to include an audio only variant.
Details can be found at the following links:
http://www.cnet.com/news/new-nexus-phones-chromecast-2-and-p…
http://www.engadget.com/2015/09/29/chromecast-vs-the-competi…
I think that's because it was just announced?
Cool thing about Chromecast 2(apart from fast play) is that players can vs each other on chromecast games.
I am surprised how often we use the chromecast, so I will get the audio one too (actually, maybe a few for different rooms).
We have a mix of android and ios devices, so it makes it easy to connect everything together.
Not available in Australia