Last.fm is just a way to track what you listen to, and get recommendations off of it. The recommendations are actually pretty good, which is why I bother with it. You set it up on your Plex server, so it’s pretty much fire and forget.

You set scrobbling on the server, so whatever you listen to through Plex will work regardless of the app.

Zuck clearly put it there as a joke/Easter egg. I know it’s weird, but dystopian multibillionnaires whose life’s work undermines the very foundations of democracy around the world can have a (bad) sense of humor too.