The downloads aren’t unencrypted, you can’t play them with any media player. Only their app can decrypt and play it. Has nothing to do with ripping them all in the month, you can do that without downloading them at all and just stream them to rip them.

The point of limiting it to 30 is to prevent someone from downloading them all to their device and then disconnecting the device from the internet permanently so you can have them forever. You’d have to do some date manipulation too in the operating system to keep the app from knowing your subscription actually expired.