http://plan9.bell-labs.com/wiki/plan9/Mouse_vs._keyboard/ind...
http://plan9.bell-labs.com/wiki/plan9/Mouse_vs._keyboard/ind...
While there have been some attempts to do that with mice (such as mouse gestures), by design, mice are about position, changes of position, with a few buttons as flags. There aren't enough distinctive signals.
Also: The Emacs mouse support is not great. It probably hasn't been a high priority.
In what way? It's certainly as good as it is in any other editor, with the addition of several very Emacs-esque mouse-driven commands. For example, right click marks the region from point to the click point and saves it in the kill rin (like M-w); double right click kills that region. Using M- does the same, but modifies the secondary selection. Using C- with the mouse pops up several useful context menus. Try playing around with C-h k <mouse button> in various contexts.
Thus, once you are no longer a beginner (the guide's target audience) you may graduate to keyboard+mouse. I don't use emacs or vi(m) or anything truly in line with them (textmate is my closest) but I have no doubt that someone who uses only the keyboard for three months and then reintroduces the mouse will show a greater capability with the tools than the same person spending the same time using both keyboard and mouse.
Guess which programmers usually do.
Sorry, couldn't resist. :)