Exaggerating the features of people and objects in systematic ways helps people to more easily assimilate both knowledge about them as well as the ability to distinguish between them in an effect which psychologists call the "caricature advantage."

Link this to using caricature as a mnemonic technique for strengthening one's memory of objects and people.

For someone who professes to be so devout, Clack's miserliness when it comes to money is downright hilarious. She frequently mentions the "pecuniary pressure" of Franklin's check, doesn't tip, and yet constantly paints herself as a generous soul. At this point it is evident that this character is a caricature of the hypocritical Christian whom Collins has built up to tear down. I expect her assessment of the sequence of events to be comically wrong.