As an Emacs users who often tries to do as many things as possible in Emacs, I would say that the more stuff you can do in Emacs, the more the various features in Emacs compound with each other, giving you more utility.

For example, I use the Verb package for making HTTP requests. So with Emacs as my HTTP client, I can do bulk HTTP request calls with keyboard macros. The HTTP requests can be stored in org-mode. I can write custom Elisp for special authentication scenarios. I can create new commands if I need them.

For this example, I can imagine (haven't used this myself) scenarios like creating a keyboard macro to shave off the first X seconds of a video usable with dired.

Some non-text-editing things in Emacs that are actually extremely useful:

  - Git via Magit
  - Managing files with Dired
  - Media player with Emms
  - RSS feeds with elfeed
  and the list goes on and on...

Using a well thought-out Emacs interface for anything is one of the biggest sources of joy in my technical life.