Two closely related threads actually:<p>[1] r/emacs - Do you use Emacs Lisp as a general purpose programming language? - <a href="https://old.reddit.com/r/emacs/comments/lly7po/do_you_use_emacs_lisp_as_a_general_purpose/" rel="nofollow">https://old.reddit.com/r/emacs/comments/lly7po/do_you_use_em...</a><p>[2] r/lisp - Is it worth learning Common Lisp for writing tools and solving practical problems if I already know Emacs Lisp - <a href="https://www.reddit.com/r/lisp/comments/lm03xe/is_it_worth_learning_common_lisp_for_writing/" rel="nofollow">https://www.reddit.com/r/lisp/comments/lm03xe/is_it_worth_le...</a><p>The first link has a mind-boggling story about air traffic control software running on Emacs.