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.
And for those looking to back up locally, there’s yt-dlp and ffmpeg! I can personally attest to yt-dlp working on more than just YouTube. I have both downloaded because yt-dlp handled some online videos better, getting them in one shot instead of only part of it, in my specific anecdotal experience, than ffmpeg. I kept ffmpeg around for reasons I honestly forgot, used them for just one big backup session and never touched them again.
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>.+)"