This strikes me as a fairly useless test, because it only works in situations where you are sure there are only 2 variables, and you're trying to determine which one is dependent. Such a situation only happens in a carefully controlled experiment--and in those situations, you can easily determine causation by creating counterfactual tests.

What people really want to know is whether statistics alone can be used to exclude hidden shared causes from an uncontrolled data set. Even the article itself uses such an example: the impact of hormone replacement on heart disease.

This test does not further that goal. I remain convinced that it is impossible. In fact to my understanding, that is the origin of the scientific method: rather than accepting conclusions from the first data set, science constructs hypotheses and tests to exclude hidden causes.