I agree that most of the slides would require further explanation but I still found a bunch of commands I've never heard of and actually could make use of, eg git bundle and git rerere.
So it's not totally worthless.
Although not totally worthless, it is nearly so. It is ~350 slides, most with a single word. To find those commands you've never heard of, you have to wade through a deluge of meaningless, when out-of-context, crap. Most readers, like me, probably said "not worth the time" after about 20 slides.