Why don't "guix pack" and "guix environment" accept manifests?

[Konrad Hinsen]

Hi everyone,

Today I tried to convert one of my Guix profiles into a Docker image, 
and naively tried

        guix pack -f docker -m my-manifest.scm

Now I know it doesn't work, but I wonder if there is a good reason or if 
this is just not implemented? The same question applies to "guix 
environment". Maybe even "guix build", although I don't see a use case 
for that. But I'd expect to be able to use a manifest wherever a list of 
packages is required.

Konrad.