Vincent Foley-Bourgon has a very nice post on why he uses Emacs. I probably like it because his reasons pretty much mirror mine. Still, I think his post will resonate with every Emacs user.
Following the old joke, Foley-Bourgon considers Emacs as an operating system and its embedded editor. The punch line of the joke, of course, is that all Emacs lacks is a good editor but Foley-Bourgon makes the case that Emacs is a superb editor and able to hold its own against any competition. It has all the usual capabilities as well as several that most editors don't have.
Any intermediate Emacs user is familiar with the operating system aspects of the editor and Foley-Bourgon covers many of them. All your file manipulations can be carried out with
dired and remote editing is easy with
tramp. There's lots more, of course, and Foley-Bourgon covers much of it.
Finally, Foley-Bourgon considers Emacs as a development environment and Lisp machine. As regular readers know, I consider these the most important aspects of Emacs. Because you have access to the same tools that the developers of Emacs used, you can extend it in any way you want—even ways not anticipated by the original developers. A consequence of this is that tons of folks have used that ability to extend Emacs in ways that benefit us all. Some of those have been folded into Emacs core and others are available as separate packages easily installed with the built-in package manager.
Foley-Bourgon's post is interesting even for those already committed to Emacs. If you know someone who is curious about Emacs and thinking of trying it out, this post may help decide the issue.