[AStonesThrow]

A CD and MP3s consist of recorded performances. A player piano roll contains the instructions for a performance, basically a transcription of sheet music, or a recording of someone performing a work. (Didn't read court findings for scope.)

Works (sheet music and lyrics) and recordings (committing it to media or storage) and performances can be distinctly copyrighted and separately licensed. But a CD track represents all 3 of those put together through “sweat of the brow”, usually by multiple parties.

[IAmBroom]

Not strictly true. Player piano rolls were not made by mechanical transciption; a human actually played the music into a recording device (at least towards the end of the era). Because of this, we have a "recording" of Scott Joplin playing one of his rags. Dynamics are not preserved, but actual timing is.