Nano has already supplanted the great EMacs and Vim as the most popular text editor of all linux distros, for though it has many omissions in functionality it scores over the older, more complete programs in two important respects. First, it is slightly simpler; and secondly it has the text "^ Exit" inscribed in highlighted text on its footer
EDIT : This sees to be going over some people's heads. It's a hitchiker's guide to the galaxy reference.
The Hitchhiker's Guide has already supplanted the great Encyclopaedia Galactica as the standard repository of all knowledge and wisdom, for though it has many omissions . . . it scores over the older, more pedestrian work in two important respects. First, it is slightly cheaper; and secondly it has the words DON'T PANIC inscribed in large friendly letters on its cover.
Sure, Notepad transfers to other GUI programs better than Nano transfers to Vim or EMacs. But that has little to do with Notepad and more to do with GUIs typically supporting similar shortcuts. Like I said, it's an imperfect analogy.
I think you missed my original point. Most people wouldn't describe themselves as "good" or "bad" at Notepad or Nano. They're simple programs designed for simple editing. The learning curve is very low for both. Advanced editors have differing learning curves, but they're all a lot more steep.
And my original point was that, because many people do only simple editing in a CLI and more advanced editing in a GUI, it makes sense that Nano became the most popular for CLI due to its shallow learning curve.