I created an issue about that.

intersystems-iris-dev-template is also forked on my GitHub with config-api usage.
You can see the differences on this commit.
I'll keep this repo up to date for testing purposes if there is any change.

@Evgeny Shvarov, @Guillaume Rongier

Hi @Guillaume Rongier ,

Thank you for this very interesting question.

Indeed, you can't tell directly zpm to load the classes in the freshly installed namespace.

You need to perform:

zn "irisapp"
zpm "install module-name"

I consider loading the code is the role of ZPM.
In my opinion congi-api shouldn't have an option to load the code.
We could add an option to call ZPM. Something like this :

{
    "ZPM" : {
        "IRISAPP" : {
            "install" : "module-name"
        }
    }
}

Execute zpm "install module-name" in namespace IRISAPP

Obviously this is subject to discussion. Community feedback would be appreciated.

About CPF module, I agree, my library has an overlap with all classes related to %SYS Config package.
For these operations the only difference is the REST expose. So, no added value if developers don't need REST expose.
However, config-api implement a part of %SYS Security package and also %Library SQLConnection.
You can configure users, roles, resources, ssl configuration, web application, enable services, sql connexions, set SQL Privileges and you don't with CPF module.

Hope answered to your questions.