While lack of permanence has long been a knock on streaming music services and iTunes, it's still unusual to see a track simply vanish from a five-year-old album. While iTunes has long sold some "incomplete" albums, they've usually been compilation albums or soundtracks where Apple didn't have the rights to sell every single song individually, seeing a song pulled off an album like this is pretty unusual.
That said, it's good news for Lady Gaga that we're living in the digital age, where this is even an option. Obviously, there's no good way to remove a song from the many CDs shipped in since the album was released, but at least she can pull the song from the dominant music platforms going forward. On the one hand, it's a bit of revisionist history (though Lady Gaga owns up to the complicated history with her song in a Twitter post), but making sure she (and Kelly) aren't making money from the song anymore is probably an important move for her.