YouTube is absolute garbage at deciding if something was “watched” or not. Sure, you can watch a playlist, but if you want to watch content in order, or if a YouTuber has a bunch of content and you want to watch all of it, often the only option is to download it and track it yourself.

That, and I’m a big fan of archiving important data. If YouTube removes a channel, or it gets hacked, or the YouTuber deletes their own content, it’s just gone. I might not feel like archiving someone’s game stream or a Minecraft tutorial, but an entertaining video I can see myself watching again? Yep, that gets downloaded.

Finally, I’m a bit of a completionist. Many TV shows have special clips they only show on YouTube, or that eventually make it to YouTube, things that don’t make it to DVDs, that nonetheless are part of the TV show; by downloading those clips, I can add it to the media I already own.