What's the point of unnamed non-type template parameters?

Question

According to the reference, the name of a non-type template parameter is optional, even when assigning a default value (see (1) and (2)). Therefore these template structs ar

Answer 1

Oh, you can access them!

template  struct Foo {};

template 
int get(Foo) {
    return N;
}

int main() {
    Foo<3> foo;
    return get(foo);
}

This might be a bit contrived. But in general for some templates you don't want to name them and then it is convenient that you don't have to.