Free users can only cast user-uploaded music
As YouTube Music struggles to get attention from users, it’s lifting the previous music casting restriction on personal music.
One of YouTube Music’s secret features is that it allows users to upload their own personal music collection to the service’s cloud locker. This means you can make playlists with music from your personal collection along with songs from YouTube Music’s library.
This feature gives users a lot more music listening freedom, but until today, people who used the free version of YouTube Music couldn’t cast the uploaded music to smart speakers. Now iOS and Android users can cast their own music without paying Google’s monthly fee.
That said, if you try to cast a song from YouTube Music’s library, it will block you and say, “Only uploaded music can play on your speakers.” It’s also worth noting that Google will remove any streaming songs from your YouTube Music queue if they’re mixed in with your personal library.
While this is a big upgrade for YouTube Music users with large libraries, it’s a bit odd that Google is still restricting free users from casting free music. For instance, if you ask a Google smart speaker to play music from YouTube Music, it will do it for free with ads and six skips per hour.
It seems that Google is rolling out this new personal library casting feature to appease people who’ve recently transitioned from Google Play Music since the old service could do this easily. In the future, I wouldn’t be surprised if Google allowed people to cast any music from YouTube Music but then turned it into a song-based radio station with ads and other restrictions.
Source: 9to5Google