The article provides an analogy, it doesn't tell you to do anything with Emacs in particular.

Besides being an everything app for you, Emacs is an (unconventional) operating system with weak boundaries between user apps. It makes it easy to modify anything, write new things, or combine two existing ones with very little code, something that e.g. Microsoft could have only dreamed of in Office with its awkward embedding that barely worked. Emacs is one the few survivors of the idea that users should program what they need, which was popular during the personal computing revolution in the 80's. Two others are spreadsheets and BASIC.

Programming turned out to be too complex for the untrained users to handle, but AI makes the idea of custom one-off apps or weird hybrids pretty damn close, that is true in practice. I see a lot of people that vibe code their own little things to get things done. That's precisely what BASIC (often shipped in the stock ROM!) was supposed to be used for.