MP4 (H.264/H.265) is the proprietary one. WebM (VP8/VP9) is open and royalty free (as is the upcoming AV1).

Less commonly supported though, most notably by Apple and some TVs (quite import for that use case).

Webm is quite a nice format actually, it's a subset of MKV that gave a good target for browser developers. The fact that patent-encumbered h264 is the only codec that is hardware-accelerated across devices is an entirely different issue.

mp4 files returned by youtube are of a lower quality than webm files.

This is one of my favorite things I don’t have to worry about with zsh + oh-my-zsh, pasted URLs being auto quoted.

you'll also want to cd to the correct folder because you probably don't want it to go in ~ or some other random location depending on what terminal you launched and how you launched it.

CLIs are terrible for people not familiar with CLIs. I love 'em, but GUIs exist (and persist) for good reasons.