Size of the user base

[swiley]

AppImage is dynamically linked to the libc runtime which IIRC is in a different place on Guix and so it won't start.

That is indeed the case, however the AppImage that I was trying (I think it was PrusaSlicer) had other missing dependencies in addition to that. The reality is that even discovering what your dependencies are is a challenge, so I don't blame the packagers. This sort of dependency hell is precisely why I use Guix and Guix System. It is still dependency hell, but only as far as getting things working, at least you have some guarantee of longevity of your solution.

AppImage is certainly worth a deeper look. It doesn't push a store and is an executable that doesn't require installing a runtime.

You really shouldn't be distributing software you don't fully understand the dependencies for. I would blame the packagers (and the author) for that.