[rurp]

I might be biased since I learned to climb before YouTube, but I find it quite difficult to learn or teach others through coaching or watching. Although I don't think that holds for the basics, if someone doesn't know what a drop knee is then a video of one would be helpful.

But past that, so much depends on subtle weight shifts and tailoring moves to ones specific body; it's hard to learn that stuff outside of just trying hard moves yourself and making small adjustments.