It's an idiosynchratic system which deviates from traditional grammar. That's a strong reason not to use it. The author claims pedagogical benefits, but provid

It's an idiosynchratic system which deviates from traditional grammar. That's a strong reason not to use it. The author claims pedagogical benefits, but provides no hard evidence or even endorsement from educational authorities. The only endorsements appear to be from beginning learners, who by definition don't know enough to make an informed endorsement.