You need internet!
I thougth I vould use the google chromecast audio to listen to my music on my NAS... no, somehow chromecast needs a continous connection to internet!!
Not a Nice device for your privacy--> you just have to agree to let it having access to all your digital medias and and grant it a continous connection to internet without knowing what the device does with your data, and leaving an opened door for hackers!!
The app seems ok for the little I used; a pity there is not one dedicated to Chromecast; for me this app seems a forcing from google to enter the hause automation world... I would give it a 2 stars if the device was not that poor...
Swefra about
Google Home, v1.20.904