It's a cool concept but like other comments say it overlooks a lot of the things that make git, git. Best way to learn? use it! Maybe just create a dummy repo and go from there with it. Maybe use the GUI tools until you're comfortable with the command line. For me personally, it was command line first. If you aren't sure about something with git, googling it will pretty much always throw out your answer.
I'm not sure I quite agree. Use it, yes, but if you're using Git as a black box then you're much more likely to be frustrated by it than if you understand what's going on under the hood. I tend to point people at "Git from the bottom up"[0] -- it gives people the understanding they need to work out the effect they require, from which they can work out which set of commands will get them there. [0] http://ftp.newartis…
I'm sure most people are probably aware of : http://try.github.io/
which is a cool little resource for learning git.