This isn't about Emacs changing the implementation language, but changing the VM that Elisp runs on. Don't worry, there won't be any Scheme in your Elisp.
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Supporting Emacs extensions written in Scheme is part of the goal I had in mind when I proposed this. That's the tangible benefit that we would get from Scheme support. If all Scheme does is serve as a platform for Emacs Lisp, it is no real advance.
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See: https://lists.gnu.org/archive/html/emacs-devel/2014-09/msg00...
Hacking Emacs with Scheme is part of the plan.
Rather, I hope the switch is made gradually, and most of all that Elisp fans don't dig their heels in against it, but rather work to make the transition smoother.
If Emacs and all of its extension code was completely rewritten in Scheme, what would be the point of sticking with Elisp? And how would using a Scheme-only Emacs be "GNU Emacs's suicide"?
What concrete value does Elisp add over Scheme?
CL vs Scheme, I could see an (unconvincing to me) argument for, but Elisp? Elisp?
Don't get me wrong. I'd much rather use Elisp than most any other non-lispy language. I just don't see anything in it to recommend it over a modern Scheme like Guile.
But I'm open to being shown the errors of my ways. What's so great about Elisp? Please enlighten me.
Bullshit.