Kirk McElhearn continues to be the best commentator on iTunes and Apple Music. From his blog:
Many record labels and artists who sell music on the iTunes Store direct their fans and customers to Apple’s store through links on their websites. However, since Apple Music went live, these links no longer work correctly.
Instead of sending someone to the iTunes Store, where they can buy an album, these links redirect to the Apple Music section of iTunes, or of the Music app on iOS (if the user has Apple Music turned on).
I don’t see what Apple has to gain from this. They’re as much better off as the artist if they sell an album.