I only pirate TV/movies, and since I never know what I’ll feel like watching it’s pretty easy to just hoard it. Takes a long time to fill up drives so adding a 16TB drive once a year or two is pretty manageable.
But tbh the main reason I hoard them and keep my Plex library full is simply to keep view stats. Prior to Plex I was constantly plagued by “have I seen this” or “what was that movie I liked 10 years ago?”. But not anymore!
Also, when the zombie apocalypse happens I’ll finally have time to rewatch Breaking Bad so I need an offline copy just in case.
Just a Synology NAS with softwarr’s and a Shield TV connected via Ethernet, works great