[SaberTail]

Off the top of my head:

For the disks: Vinyl can get permanently scratched. The disks can get warped. The playback needle can put too much force on the groove and damage it.

For the playback: It's incredibly difficult to get a motor to spin the disk at a perfectly uniform rate, so you get distortions in the frequencies being played back known as "wow" and "flutter". The groove is not the audio exactly as recorded, but instead equalized to lower bass frequencies so that the needle doesn't skip out of the groove. This RIAA equalization has to be undone for playback, and if it is done with analog components, it's never going to be exact.