This would be useful when there are multiple copr config files. copr reads config from default place ~/.config/copr. I have two configs for Fedora and internal one, and the latter is the default. So, when I want to build packages in internal copr instance, I have to use copr-cli instead, that is because copr-build does not allow me to specify an alternative configuration file.

The cli with this new ability could be

fedpkg copr-build --copr-config path/to/config myproject