Black has successfully protected the knight at c6, but unfortunately he has blocked his bishop at f8, and Black would prefer to have his knight at f6. But this defence has one advantage over the Murphy's -- Murphy's Defence is too familar! Most players playing White would be uncertain what to do at this stage. On the other hand, every serious player would know how to respond to Murphy's Defence. The Alapin/Cozio is certainly a bona fide defence, and gives a good example of how a weaker move can actually be the better move just because it is less familar.