That is not quite true. The CCA streams directly from the router. The smartphone or tablet is little more than a remote control. One the program material is selected on the phone or tablet and the connecton is handed over to the CCA, you can turn off the phone.
This is correct; CCA works similarly to DLNA/UPnP when streaming music files. For example, if you are using a NAS drive to store/serve your music files:
- The NAS drive is the source (i.e. UPnP server) for both CCA streaming and UPnP streaming
- The CCA (or CCA+DAC if using the CCA's toslink output to feed a DAC) is the equivalent of a UPnP renderer
- Your smartphone or computer (running an app that supports Google Cast) is the equivalent of a UPnP Control Point
When you use your preferred app (that supports Google Cast) to choose a song/music file from your NAS to stream to the CCA, you (generally) can close the app after playing the song, as the CCA streams directly from the NAS source, not through your app (unless your source music files are stored on the same device that also runs your app).
If you've closed the app after playing your selected song, you will have to reopen the app in order to choose and play another song.
What makes CCA more versatile than DLNA/UPnP is that it is supported by music streaming services such as Spotify, Tidal, Amazon Music, Google Play Music, etc. When using CCA to stream from a music streaming service, it's the same idea as streaming from a file source; the CCA streams directly from the music streaming service; you use the music streaming service's app to select the desired music stream and also the CCA endpoint. The app merely acts as a "traffic controller" to feed the selected music stream from the streaming service to the CCA.
I agree that the CCA is not a standalone streamer, and so should not be included in the chart above