Speaker clips can only take in about 1/2" of bare wire. Yung speaker pin, which I think is about an inch long, eh hindi talaga maiipasok ng sagad.
Using pins is not advisable, you'll have only 2 (or at most 3 kung didikit sa side) tangential contact points between the pin and the clip. Graphical representation, yung parallel lines ang clip, yung pin ang circle:
Accordingly 37, 49 or more small circles (wire strands) pressed by those parallel lines will have a much greater number of contact points for better conduction.