For graphics programming tutorials a video is a huge help. The huge problem with text articles about complex dev topics is that errors compound - if you're following along and you make a mistake early on you won't necessarily know until much later, by which time it's a lot harder to figure out where you went wrong. Being able to see what was supposed to happen at each step makes it much easier to follow.

Also, with a live stream in particular, you frequently get to see the author make mistakes and stop to figure stuff out rather than just the edited and polished perfection of a published article. I find that really helps to humanize the author, and gives me confidence that even though I'm making a lot of mistakes I'll be able to get to a finished product eventually.