> The artist, JT Nimoy, was an Emacs user but still thought it would be fun to set up a dichotomy--some fun details on this blog

I don't see any details about setting up a dichotomy in that article (just that the author was a happy Emacs user). Or maybe that was in that HN meetup you mention?

and the comment there about using emacs for the different shells in different modes possibly explains the un-resolved nit in TFA about proportional and monospaced fonts in different areas