Youtube wants me to concede too much JS execution on too many domains (I block strictly), or else I can not skip the ads. It becomes a huge annoyance when I'm watching my favourite TV show that's also uploaded to YT and I have the same idiotic Grammarly ad in my face every 10 minutes. But I can easily run mpv <url> and watch, without looking at ads that are completely uninteresting and persistent enough to feel harassing to me (youtube is showing me grammarly ads since months, almost nothing else; so much that I loathe grammarly now).

Also when watching a video, with mpv (which uses youtube-dl for youtube videos etc., I can pin a small video window on top of all other windows and continue doing other stuff on my laptop.

It’s also the most reliable way to get hardware decoded YouTube on Linux.

Firefox and Chrome don’t support it last I checked, and I’m not sure if they even have GPU rendering on Linux by default.

Some players can hook into youtube-dl, so streaming is still possible.

I downloaded a bunch of videos for watching on the train when my commute was 3 hours and the 4G connection was absolute shit. Youtube-dl saved my sanity.

That is the main reason I download stuff from youtube. I am an academic and I've had more than one video I used in a class or wanted to use for research disappear. So now I download copies of all videos that I think I might use in a class or for research.

Not just for that, though that's a good reason.

I use this to download for offline viewing (such as when traveling), or to download and number an entire playlist at a time into a directory full of video files.

I use it because my internet at home is awful, and so I can either download it at home so I can watch it in one go later, or download a video when I am at a place with better internet.