Animator works on show. Show airs.

Show has no physical DVD/BD version

Show only exists on streaming service or on DRM-locked "buy and own but not really" services.

Show gets pulled from internet because some corporate license expired or some shit like that.

Show no longer exists anywhere other than the corporation's hard drive and pirates' seedboxes.

Animator needs to show their own work as part of a video portfolio to a prospective employer. A scene they made for a well-loved show is great portfolio material.

The corporation ain't sharing. Not until someone sues for the right to get a hard copy of the show they worked on -- Which given how the entire American state does when corporate interests fight any other interest, is something no one animator is willing to do as it'll probably not just drain their finances, BUT has a legitimate chance of fucking over every OTHER animator down the line.

Ergo.
Animator needs to pirate it.

In ye olden days, shows often aired only on TV and didn't get VHS releases. But animators would often just. Tape the show they worked on. Off of the telly. With a VCR.

Which in practice is the same thing as what the pirates are doing, creating a local copy of media that is airing, but corporations don't want you to realise that. So. Here we are.