If you can point a package manager at a git repo and use it like package, this is accidental convenience. Source code repositories should be factored as source code, with a build step to transform them into packages. For some languages that means compilation, for others it means transpiling, minifying, or just copying files. The resulting artifact is a different shape, designed for consumption.
If you use git for packages, then your repo becomes the package boundary. You no longer have the option of producing multiple packages from one repo, or even one package from multiple repos.
If you use git for packages, then your repo becomes the package boundary. You no longer have the option of producing multiple packages from one repo, or even one package from multiple repos.