The only streams I typically watch are conference type presentations that I could not see live. For me personally I find most educational type streaming content is inferior to the same material presented in text. This is most likely because I learned my fundamentals via text books when there was no such thing as "streams."

If I try to give a more objective critique I think the act of writing something is more thoughtful than just saying it. Live content rarely, if ever, will have the same sort of detail as something written in a book because doing so on camera would be unwatchable tedium.

I agree with others that streams could be useful for introduction to topics (ex: conference presentations) but in my opinion, fall short beyond that.