Is there any difference between this two versions?

I see a problem in C++ Primer 5th edition, which goes:

We could have written StrBlobPtr’s deref member as follows, Which version do you think is better and why?

std::string& deref() const
{ 
    return (*check(curr, "dereference past end"))[curr]; 
}

---

Here is the simple StrBlobPtr class:

class StrBlobPtr {
public:
    StrBlobPtr(std::shared_ptr<vector<string>> &p, size_t sz = 0):wptr(p), curr(sz) { }
    string& deref() const {
        auto p = check(curr, "dereference past end"); // !!! Here is the origin version
        return (*p)[curr]; // !!! Here is the origin version
    }
private:
    std::shared_ptr<vector<string>> check(size_t i, const string &msg) const {
        auto ret = wptr.lock();
        if (!ret) throw std::runtime_error("unbound StrBlobPtr");
        if (i >= ret->size()) throw std::out_of_range(msg);
        return ret;
    }
    std::weak_ptr<vector<string>> wptr;
    size_t curr; 
};

---

At first, I guess that there are some difference when any exception throw. so I write the test codes as follow:

StrBlobPtr p(make_shared<vector<string>>({"test", "t"}), 2);
cout << p.deref() << endl; // should be out_of_range.

But the result is throw the out_of_range regardless of which version. I can't see any difference in this two versions. What is the point of this problem?

If there isn't any difference, I prefer the (*check(curr, "dereference past end"))[curr];, cause there only one line. looks simple.

I am very grateful for anyone can help me...