Purpose: To show that Spain isn't any better under a republic. Spain is free, but there is a huge contrast between the rich and poor. There is poverty and times of economic hardship, which is a reflection of the world wide effects of the Great Depression.
Value: It is valuable because it illustrates that some individuals resented the second republic. Maybe they were thinking that times were better under the monarchy or even the dictatorship.
Limitations: Obviously I don't know the date or the place this cartoon was published, so that is a limitation of truly understanding what the artist is depicting.