I honestly don't know about the state or progress of Guile Emacs. I know it exists, but I haven't followed it beyond that.
Assuming it gets "finished" (is any software ever finished?), it should be no-brainer as long as it provides backward compatibility with old elisp code. And open up the emacs ecosystem to Scheme and Javascript, which could make it much more attractive to newcomers. But, as they say, I'll believe it when I see it.
The trouble with Hurd, IMHO, is that I've run out of jokes. We used to joke that it would run Duke Nukem Forever out of the box, but that one actually got finished. Then it was Perl 6, but that has arrived, too. Star Citizen maybe?
It was actually started in 2000 and doesn't seem to have progressed since 2014: https://emacsninja.com/posts/state-of-emacs-lisp-on-guile.ht...
Plus, even if it's finished, will it get any traction in the ecosystem? Will the ecosystem start moving to it to take advantage of its unique benefits? Who knows?
Bonus: Have you heard of GNU Hurd? :-)