I've used org-mode with inline code a few times now, and it is terribly expressive and useful when you want to show reports with "live" results in them, etc.

That said when it came to formatting my Emacs init file, with descriptions, and justifications, I chose to use markdown:

https://github.com/skx/dotfiles/blob/master/.emacs.d/init.md

Markdown allows text, and code, to be mixed, and while there is no inline expansion support or other neat features it is minimal enough that it was painless to write and process.