My spouse uses the speakers pretty often, but even the old app wasn't great, and I gave up on it. Why can't I just cast the music from my Youtube music app? Why do I have to connect Sonos to Youtube, then wait for a separate app to pop up?
I just end up playing music in my headphones, or on my phone speaker. The quality is worse, but the experience is better.
Because the YouTube app developers haven't implemented it? Casting via spotify works flawlessly in my experience, whether using airplay or letting spotify discover the speakers. No app hopping required.
TBF that's because clicking on a Sonos device in Spotify uses their own special-sauce Spotify Connect, not AirPlay/Cast. So you're basically using the Spotify app as a remote for the selected Sonos device vs AirPlay/Cast which are transmitting (potentially a reference to) the underlying audio stream.