I never fully "got" emacs even though it was the popular editor during university times and I occasionally use it for quick server admin stuff. Today I feel it has missed its boat with good looking and user friendly stuff available like Sublime Text, Atom, Eclipse and even cloud IDEs. I cant help but to laugh quietly to addons like this.
Once you have that "everything is text" realisation, there are two ways to make the most of it. One is to have an editor that's easily called from other places (e.g., vim) and the other is to have an editor that can be integrated into everything (e.g., emacs).
I started using emacs over a decade ago, and it keeps growing and changing to best suit my workflow. And yes, that includes reading mail.