After some serious mental gymnastics, I think that fundamentally the plans are fine, and they're likely targeted at users of Spotify and other music apps that haven't themselves implemented the Siri Support on the HomePod. The major problem with it is the poor messaging around what exactly it is. If Apple said "This is for you folks that still don't have Spotify on your HomePods", people would say. "Woah, if this was $2 a month, that would be pretty neat!"
I imagine some PR guy at Apple said, "we can't outright slate Spotify for not implementing their app on our smart speaker, so we have to be careful in what we call this thing"
I imagine some PR guy at Apple said, "we can't outright slate Spotify for not implementing their app on our smart speaker, so we have to be careful in what we call this thing"