Even if you don't have to type it (using macro/template), you still have to look at it. Visual clutter or overload, I say.

This is for an (internal) project, so chances are greater that every developer knows it.

It follows DRY principle. If I can group several statements into a sub, why can't I also group several directives/preamble into one line?

The Foo::common does provide something Foo-related: setting policy for every Foo module.