Discuss: theoretically.describe

[hypesystem]

Whereas theoretically.it sets up a single test with a varying value, theoretically.describe would set up an entire section with a varying value:

describe("NumberStack", function() {
  theoretically.describe("empty()", [
    emptyNumberStack,
    numberStackOneElement,
    oneHundredElementNumberStack
  ], function(numberStack) {
    it("removes all elements", function() {
      numberStack.empty();
      expect(numberStack.length).toEqual(0);
      expect(numberStack.pop()).toBeFalsy();
    });
  });
});

(This may not be the best example as it only has a single it in the theoretically.describe. What would be a good example, where several small tests would use the same varying value?)

What are pros/cons of this feature? Should it be added?