Comment by smg

The biggest difference between Emacs and any other editor is that instead of thinking about Emacs as an editor you need to think of Emacs as a programable workflow enabler. Using Emacs without learning Elisp is like carrying a bike on your shoulders instead of riding it. Once you get to the place where you can confidently write Elisp to solve your problems, you will miss Emacs deeply when you have to use any other application. You don't need to write extensions and open source them for other people. All you need is the ability to create Elisp code that does what you want exactly how you want it.

The best way of learning Elisp is reading the source code that is distributed with Emacs. Do a git checkout of Emacs and read Elisp code written by Stefan Monnier. Stay away from org-mode elisp - the quality of that code base is highly suspect.