If this happens to be something where you edit text, it's similar to a text editor.
If it happens to be composing music, cutting videos, playing games, visualizing your agenda, or many other use-cases, there is no text editor involved at all.
@publicvoit Emacs is an editor. It is not a platform, that is GNU Emacs -- which even the GNU web site explains.
Thesis by RMS on Emacs on the topic is a good read.
As for arbitrarily limiting on what you consider valid or acceptable -- what nonsense. There are plenty of people that use ersatz Emacs, XEmacs, LW, Hemlock or what have you.
@publicvoit Sorta weird question, even GNU Emacs is a niche.
But you have CLIMACS, Hemlock, you have ersatz emacs like mg. In the "back from the future" world you got ZWEI. In the proprietary world, Lispworks has a fork of Zwei.
GNU Emacs is the best Emacs, but Emacs is just an editor -- with a specific UX.
I think it is a mistake to equate e.g., Magit and Emacs -- they both run under GNU Emacs but they are very different in how they work.
@amszmidt@jtr After working for almost three decades with Emacs, I only stumbled over XEmacs and GNU Emacs.
I've never stumbled over your other examples. Emacs might be a niche on its own, yes, but your examples don't even qualify for a niche worth mentioning IMHO - at least what their practical impact means. YMMV.
Emacs is a Lisp platform, no editor (only). I'd love to see your reference from the creators or Emacs. Might be a definition from the 70s/80s where this might have been correct.
@publicvoit@jtr I don't see how it proves anything -- this is just confusing implementation and one specific program in that implementation -- GNU Emacs vs. Emacs. There are more Emacs editors than the one GNU Emacs has.
I'm not sure I explained it in a way that makes sense. The problem is not explaining what tool Emacs is or what kind of software; that's pretty easy: It's a text editor.
Asking what is Emacs sells it short and doesn't explain why so many people swear by Emacs every day.
Perhaps a better question is why. So, as the blog's title suggests, don't ask why; I'll explain anyway.