Commentators have described section 39's adoption as the equivalent of a "quiet revolution" that "is breathtaking in its potential transformation of the traditional contractual landscape." Caprice L. Roberts, Restitutionary Disgorgement as a Moral Compass for Breach of Contract, 77 U. Cin. L. Rev 991, 993 (2009). What is so revolutionary about this provision? How does it differ from the traditional approach to contract damages described in your textbook?