Purpose: The artist is depicting the dictatorship of Primo de Rivera as a vicious dog/beast that is being defeated by a regular working man. The cartoonist is clearly against the dictatorship and illustrates that days are happier because the defeat has occurred.
Value: It is valuable because it illustrates anti-dictatorship sentiments. It also illustrates this party's progressive and socialist views.
Limitations: La Libertad held a republican view and was clearly against the dictatorship, so obviously the depiction of the dictatorship was very skewed.