Guix uses patchelf.

Patchelf is very useful anytime you want to change the location of dynamic loaded libraries but don't want to set LD_LIBRARY_PATH.

It is used in more places than you might originally think.

We don't use patchelf for any official package definition. We have a package for patchelf, but it's only really useful when you have pre-built binaries that you can't rebuild from source.

The main guix monorepo may set that hard requirement the everything just be built from source, but if you want to run closed source software than your only two options are make a fake FHS or use patchelf. Both methods have pros and cons. Only patchelf makes the result work well with other closed source programs.

While from a philosophical point of view guix is pure, real world usage often needs closed source software.

Yes, for pre-built binaries you can't really get around patchelf. For example, that's also how CUDA is packaged for Guix.

GoboLinux also uses patchelf.