EDIT: looks like even in this thread people are suggesting to use Lua instead of elisp. smh
Now imagine trying to explain to them the concept of subtracting a hundred from a billion and the most straightforward way to deal with that is a decimal numbering system. I think they'd kill you for blackmagicfuckery on the spot.
Well, if that comparison feels condescending, let's imagine ancient Romans - with all their sophisticated culture, economy and traditions. They wouldn't kill you, but still the idea of a number such a billion would probably terrify them. They'd probably be like: "dear sapientissime señore, we respect your wisdom, but we rather use... Lua"
Oh, I found the answer on my own, with the help of LLM. For a billion you can use M̅M̅, which technically would mean a thousand thousand thousands, and to denote the calculation above you'd write - M̅M̅CM. But my point still remains relevant - this is the modern extended version of Roman numerals. In ancient Rome they typically never would go up to a billion.
Probably Stallman would object that Lua doesn't have read (apart from eval) and print.
As for performance, LuaJIT performance is better than any Common Lisp or Elisp, and dramatically better than the first 35 years of Elisp, before native-code compilation.
XEmacs, much better than Emacs back then, was my rescue for not having IDE culture back in my early UNIX days. We're talking back when Xenix and DG/UX would be known names to anyone working with UNIXes.
Nowadays, while Emacs key bindings and elisp might still be burned into my brain cells, I no longer reach out to it.