Apple Music’s performance and audience retention has been the subject of much digital ink, and this debut is likely to prolong interest in the topic. Last month, CEO Tim Cook confirmed that it had more than 15 million users, including more than 6.5 million paying subscribers. That was all on Apple’s own hardware, and it’s unclear how much demand there might be in the Android camp for a music service made by the competitor. But this does open up the possibility for another jump, if only a small one, in audience numbers for the fledgling Apple Music.