Backing up Blu-rays and watching them on your device.

Unlike with music, you can't buy DRM-free Blu-ray quality movies outside of Blu-ray. If you stream a show or movie, even if you have "bought", you don't own it.

Retro gaming and media rips.

You can literally pop a ps2 game and just play with pcsx2, don't even have to rip it. Given the recent pushes towards "you'll own nothing and fuck you if you don't like it" it isn't surprising to me that a company is offering a path back to media ownership.

Based on the specs for the machine, that's the goal as well. I wouldn't consider a 16 GB kit sufficient for much else than a media/web machine anymore, and that's the default on the advertised rig

I have several use cases, a big one being that it gives me an alternate storage medium for backing up home photos and videos. Obviously there's caveats on how long BD-Rs last (although M-discs should outlast me) and the issue of needing a player in future, but it gives me more peace of mind knowing that I can backup these sorts of things to different storage types (external hard drives are all well and good until they're corrupted by power issues or user error, or you want to keep a copy at a relative's place and it's a multi-hour trip... with optical media you can just keep adding discs to the offsite backup as needed and update the external HDD less frequently).

The other major use case I have has already been mentioned - backing up Blurays that I've bought (or, in the case of a few shows I like, being able to compare the DVD vs Bluray frame by frame).

I have one but it is external and I use it to rip BluRays. Shh don't tell anyone.

I use M-DISC (not all blu-rays are M-DISC) for backing up important documents.