YouTube has almost no original knowledge.

Most of the "educational" and documentation style content there is usually "just" gathered together from other sources, occasionally with links back to the original sources in the descriptions.

I'm not trying to be dismissive of the platform, it's just inherently catered towards summarizing results for entertainment, not for clarity or correctness.

YouTube has a lot of junk, but there are also a lot of useful videos that demonstrate various practical skills or the experiences of using certain products, or recordings of certain natural environments, which are original, in the sense that before YouTube you could not find equivalent content anywhere, except by knowing personally people who could show you such things, but there would have been very small chances to find one near you, while through YouTube you can find one who happens to live on the opposite side of the World and who can share with you the experience in which you are interested.

While there is a lot of low-effort content, there is also some pretty involved stuff.

The investigation into Honey’s shenanigans[0] was investigated and presented first on YouTube (to the best of my knowledge). The fraud in Minnesota was also broken by a YouTuber who just testified to Congress[1]. There are people doing original work on there, you just have to end up in an algorithm that surfaces it… or seek it out.

In other cases people are presenting stuff I wouldn’t otherwise know about, and getting access to see it at levels I wouldn’t otherwise be able to see, like Cleo Abram’s[0] latest video about LIGO[1]. Yes, it’s a mostly entertaining overview of what’s going on, not a white paper on the equipment, but this is probably more in depth than what a science program on TV in the 80s or 90s would have been… at least on par.

There are also full class lectures, which people can access without being enrolled in a school. While YouTube isn’t the original source, it is still shared in full, not summarized or changed for entertainment purposes.

[0] https://youtu.be/vc4yL3YTwWk (part 1 of 3)

[1] https://youtu.be/vmOqH9BzKIY

[2] https://youtu.be/kr3iXUcNt2g

[3] https://www.ligo.caltech.edu/page/learn-more

I'm not looking for original knowledge when I go to YouTube to learn something. I just want someone who's good at explaining a math concept or who has managed to get the footage I want to see about how something is done.

I think that's the wrong metric for evaluating videos.

I've noticed that the YouTubers I enjoy the most are the ones that are good presenter's, good editor's, and have a traditional text blog as well.

You are being dismissive, though. There is no "original knowledge" anywhere. If the videos are the best presentation of the information, best suited to convey the topic to the audience, then that is valuable. Humans learn better from visual information conveyed at the same time as spoken language, because that exploits multiple independent brain functions at the same time. Reading does not have this property. Particularly for novices to a topic, videos can more easily convey the mental framework necessary for deeper understanding than text can. Experts will prefer the text, but they are rarer.