What is the difference between 'toBe' and 'toEqual' in Jest?

Jest documentation reads:

toBe just checks that a value is what you expect. It uses === to check strict equality.

And for toEqual:

Use .toEqual when you want to check that two objects have the same value. This matcher recursively checks the equality of all fields, rather than checking for object identity—this is also known as "deep equal". For example, toEqual and toBe behave differently in this test suite, so all the tests pass.

    const x = { a: { b: 3 } };
    const y = { a: { b: 3 } };

    expect(x).toEqual(y);
    expect(x).toBe(y);

In this case, toEqual passes but toBe fails. I understand that toEqual passes because it does a "deep equal" check. Why is the toBe failing in this case? Also, are there best practices for using toBe and toEqual (not just in Jest but in other testing frameworks, too)?