Can't understand why this comment is so far down on the page. Apple Music has 98M users [1]. Let's say conservatively users listen to one song per day and update metadata on one song per month. That's 30 * 0.5 MB * 98M ~= 1 petabyte extra per month sent over the wire to save ~4 MB * 98M ~= 392 terabytes per month from being written to disk.

Those 0.5 MB presumably also need to be written to disk, making this a trading away of 392 TB in disk writes in exchange for 17 PB over the wire + 17 PB in disk writes? I'm sure this is overly simple and overlooks a lot of technical details, but I can't see how this can be worth it.

[1]: https://www.businessofapps.com/data/apple-music-statistics/