Why isn't move constructor being called in this setup?

Question

UPD: The linked duplicate question do indeed resolve the issue. Thank you, everyone, for your suggestions.

Suppose I have the following class:

class NonCopyableInt {
public:
    NonCopyableInt(const int &source) : data{source} {

    }

    NonCopyableInt(const NonCopyableInt &val) = delete;

    void operator=(const NonCopyableInt &other) = delete;

    NonCopyableInt(NonCopyableInt &&val) {
        data = val.data;
    }

    int data;
};

Now, I'm using it this way:

template<typename T>
ostream &operator<<(ostream &os, const vector<T> &vec) {
    for (const auto &v : vec) {
        os << v << " ";
    }
    return os;
}

ostream &operator<<(ostream &os, const NonCopyableInt &v) {
    os << v.data << " ";
    return os;
}    

int main(){
        {
            cout << "partial move" << endl;
            vector<NonCopyableInt> v;
            v.push_back(NonCopyableInt(1));
            v.push_back(NonCopyableInt(2));
            v.push_back(NonCopyableInt(3));
            v.push_back({3});

            vector<NonCopyableInt> vref;

            cout << v << endl;
            cout << vref << endl;

            vref.push_back(move(v[0]));
            v.clear();

            cout << v << endl;
            cout << vref << endl;
        }

        return 0;
    }

This works perfectly fine and as expected. I am able to move objects between vectors without copying them. However, here is my question:

Why can I do this:

v.push_back({3});

But can't do this(causes the following compilation error: error: call to deleted constructor of 'NonCopyableInt'):

vector<NonCopyableInt> v{{1},{2}}

? My guess is that when I call vector constructor, it can't accept element by rvalue or what?

Thank you.