Having taught Git to a number of people, I disagree that it’s easily understandable. It’s easy to understand the general idea of how it works, but actually productively using it is an entirely different matter.
I find it easy to teach, thanks the concepts being simple and clear. I don't have to transfer a lot of information before people can start reasoning about things themselves and independently finding out more.
I always try to make sure people understand two things:
1) The history tree (==how to read the metro-map that is gitk)
2) Distribution, that you are responsible for syncing with others, not the other way round
Almost everything else I prefer the students at least try to figure out themselves.
Of course, I may also be a terrible teacher.