YouTube Music at last look is still on track to be the replacement for Google Play Music, but Google is adding features from the latter app into the former. For example Google Play Music allows users to upload their entire library to the service so they can stream it from anywhere. This is something YouTube Music still doesn’t do.
On the same note, Google has added local music integration to Youtebe Music.
With local music integration, users who have music stored directly on their phones and SD card can now make use YouTube music to play those files. If you have a subscription to the YouTube Premium service and have a song which isn’t on the service, there is now a method to have YouTube Music play it.
Sadly, Google hasn’t yet implemented the library migration between Google Play Music and YouTube Music which many of us have been asking for.
No word on when this feature will come to iOS.