How did you learn Guile ?
Here is my experience so far :
I actually learned Scheme in CS212 at Cornell (which, incidentally, I bombed at the time, but it was due to the pacing, not being unable to handle the depth), so it was pretty much a no-op for me.
Fundamentally it's a pretty simple language. Once you grasp those details, the rest kind of falls into place where you look at some code and go "Oh, THAT'S what it's doing".
I also answered your comment there.
This is exactly my feeling as well. The fact that Guix uses Guile (which is basically Scheme, a Lisp) throughout the entire process (even from the preboot environment!) is kind of a big deal. Plus the commandline UI is just better (at least if you prefer your package manager to look like "brew install <packagename>" instead of "pacman -Ssyyu <package>"). I know the "nix" command is making headway there but it's apparently also being rewritten at the same time and is basically still a buggy clusterfuck plus I hear there's an added complication of friction between the older nix devs and the newer committers working on the newer stuff.
I almost wish there was a "declarative Bash" variant on a fork of Nix that would allow people to lean on Bash knowledge but would only permit declarative style operations, so you could get the underlying Nix goodness but would have a more familiar (to most) declarative command language on top of it... or even better, something like https://wryun.github.io/es-shell/
... but you'd still lose the nix momentum