Youtube being the dominant video streaming platform, its decisions can have problematic ripple effects. And as it’s not unusual for their changes in rules to retroactively nuke videos from the site, a preservation tool such as the one linked is a welcomed one.
Functionally, it’s pretty similar to Archive Today in that it’s pretty basic and straight to the point.
Also storing videos is hella expensive, so if you find the tool good and you have some spare change, please donate to it.
Iirc ffmpeg is the basis for most modern conversion tools, including some functions from yt-dlp.
Also a matter of taste, I suppose, but yt-dlp can also include the description of a video to the comments section of a video/audio’s metadata. Programs like VLC can show that. Iirc the flags needed are
--embed-metadata --parse-metadata "description:(?s)(?P<meta_comment>.+)"