vis.usage claims:
Accessing a module, for example, would mean looking inside of it (to import more items). On the other hand, accessing a function would mean that it is invoked.
I don't understand what this is supposed to mean, other than perhaps "usually, the reason you might want to access a function is to invoke it".
But of course while usually true that's not always true.
mod m1 {
pub fn f() {}
}
fn main() {
let p: fn() = m1::f;
println!("{:?}", p);
}