Strongly disagree with that one. A UI that lets you work in the most efficient way (e.g. vi) can also be well designed, even if it's incredibly difficult to learn.
> creating a fresh learning repo for dedicated learning for fear of losing data while using the tool in your "real" repo is the ultimate red flag in terms of usability.
Again, strongly disagree. Git is a powertool. You don't let loose a powertool if you don't understand how it works. Creating a fresh learning repo is merely acknowledging that you don't know the tool well enough yet. There's nothing wrong with that.
There's a big difference between being noob-friendly and being user-friendly. Personally, I hate noob-friendly tools, because they tend to just get in the way.