I guess it depends on what you mean by shoot themselves in the foot. There are major differences in philosophy and bar the "superficial" differences these are quite different projects.

For one nix simply doesn't have a project focused on bootstrapping. As another example compare rust bootstrapping[0] versus using a rust binary[1]. Nix also has no alternative to guix challenge[2] or guix pack[3]. Even a comparison of their documentation shows this difference.

The question is if you consider these measures useful, and if you think bootstrapping is even an issue in the first place. To me this is the bigger question when comparing the two projects, as depending on your philosophy guix is either taking necessary precautions or unnecessary mitigations.

Given posts like this their marketing is okay, I haven't seen much unnecessary childishness - but both projects are fundimentally complicated thus have to invent words for concepts and there's nonguix[4] and most people run nix on GuixSD for their non free software needs.

I doubt guix will be more popular than nix anytime soon, but I don't think NixOS will be more popular than Arch anytime soon either.

[0]: https://guix.gnu.org/blog/2018/bootstrapping-rust/

[1]: https://github.com/NixOS/nixpkgs/pull/85542

[2]: https://guix.gnu.org/manual/en/html_node/Invoking-guix-chall...

[3]: https://guix.gnu.org/manual/en/html_node/Invoking-guix-pack....

[4]: https://gitlab.com/nonguix/nonguix