If Guile had more of the "batteries" from the Gauche standard library it might be the perfect all-purpose Scheme. But for just writing a simple application quickly and easily it's been impossible to beat Gauche for me, it's on par with Python and Ruby in that regard IMO.

Aside from the debugging & testing I already mentioned, going only through guix is a tough sell considering the very tiny amount of people that use it. It's also incredibly slow and doesn't have many packages available. Even for Emacs, it has this weird way of going around Emacs-installed packages (GNU or MELPA channels). Just like Guile docs, it also doesn't tell you of a good way to do things, it only says "here is what exists" with too little guidance imo. It means people have to figure out how to setup things properly on top of all the rest. It makes for a terrible onboarding.