I didn't watch the video but I've gone through that guide you linked, it's excellent but I don't think it's a great comparison. It only implements a handful of commands and doesn't go into the same amount detail. The Building Git book goes way more into the interesting bits.
My whole point was it is way easier than one thinks and there are good free resources available. Once you do the basic of git filesystem , object storage and sha basics implementing the rest of the API is trivial in comparison.
It's true that you can find most content somewhere freely available in various disparate corners of the web and everything is trivial if you have the info... but that's a strange reason to automatically reject a book you haven't read.
