You need to change the way you frame this phenomenon. Don't think of Emacs as an editor, but as a fully-introspectable and runtime-modifiable OS built on the "plaintext is king, but 2D" paradigm, that has a high-level language runtime (elisp), and comes with a set of default applications, one of which happens to be a text editor.
The desire to never leave Emacs isn't about making it slightly easier to view e-mails next to code. It's about making it possible to use the same autocomplete, same syntax highlighting, same recursive regex search, same multicursor editing, same whatever "magle this thing and put it in your calendar" hack you wrote the other day, on anything that's made of mostly text - e-mail, chats, code, prose, process lists, directory listing.
You'd probably have to experience it to believe it, or at least see some Emacs-as-OS user live, but this unification of all computing under a sane, end-user programmable, highly ergonomic interface can boost your productivity and experience in a way that isn't seen anywhere else today, not even during regular Linux use.
The desire to never leave Emacs isn't about making it slightly easier to view e-mails next to code. It's about making it possible to use the same autocomplete, same syntax highlighting, same recursive regex search, same multicursor editing, same whatever "magle this thing and put it in your calendar" hack you wrote the other day, on anything that's made of mostly text - e-mail, chats, code, prose, process lists, directory listing.
You'd probably have to experience it to believe it, or at least see some Emacs-as-OS user live, but this unification of all computing under a sane, end-user programmable, highly ergonomic interface can boost your productivity and experience in a way that isn't seen anywhere else today, not even during regular Linux use.