Short answer: yes.So it works well for whole home audio? Do you cast from your phone for that?
I (primarily) use two seperate apps/programs/services for music:
1) Google Play Music for a "streaming subscription" that integrates pretty seamlessly with free cloud-stored copies of my own personal music library (with CD-quality and hi-rez FLAC files converted to 320 kbps MP3's)
2) Plex for my own personal music collection (including a small selection of "hi-rez" albums but a pretty subtantial collection of bit-for-bit CD-quality rips using Exact Audio Copy).
Both apps support Google Cast/chromecast natively within the app (do not require "casting screen/device").
I primarily play music using:
1) My Android phone
2) My Android Tablet
3) My Win10 laptop
I can play music using either service from any of those three devices, and all 6 combinations support "casting". Within the Google Home app you can group up any/all combinations of Chromecast Audios and/or Google Homes and give that group a name. When you click to "cast" and you get a list of devices, any "group names" you've created also appear on that list. If you click on the group, casting begins playback (assuming all sources/speakers are powered on). If/when one of my speakers in the group is powered off, playback begins for me pretty seamlessly/instantly by simply powering the system on and waiting 3-5 seconds...
Whole home audio is the primary reason why I bought four of them.