Other people in this comment thread made good point about value for viewers, so I'm not going to focus on streamers in my response.

> blog, tutorial video, stackoverflow post, book, etc

Well, how does one records a tutorial video? It is not that easy, there are a lot of details: language, library, length of video, format(i.e. what things to explain, in what order, etc, etc). Streaming is straightforward, you code as you normally would and explain stuff as you go. As for information density, I think it is possible to speed up "boring" parts(e.g. silent thinking) in recorded videos. We aren't 100% sure, but we're coding a prototype.