Github itself is a Github project, therefore using anything other than the API would be some code duplication. Merging, Pull-Requests, Branches, Issues: all this is already covered when using the normal API.
I'm sure it could be "more efficient" when having code explicitely for this purpose, but then again you have to maintain to different code bases which do the same.
Besides that it's a shame that the option to just get the stream running in VLC is such a hassle (with VLC I get much lower CPU usage + the ability to freely move and resize the video and place it somewhere on my second screen, even fullscreen)
I'm currently reading it. It gives a rather basic C introduction (I skipped it) but then it goes into explaining how to inject shell codes, using buffer overflows and getting deep into the assembly of programs. It's definitely great for a start.
I'm sure it could be "more efficient" when having code explicitely for this purpose, but then again you have to maintain to different code bases which do the same.