The Chromecast Audio allows me to plug it into any standard stereo. Bang for the buck I can get much better speakers for the dollar when buying just normal speakers instead of "smart" speakers. I then plug the Chromecast Audio into it and get the same ability to Cast to it, and include it into groups. The ability to add it to Cast groups is one of the key reasons I like it over just a Bluetooth connection.

So to sum up: * Bang for the buck get better audio quality * Still get all of the same Cast features (WiFi casting, group casting, etc.)

Hope that helps! :)