The time spent with Paul changes the lives of the Kittredges, especially Quisa's, and most importantly, gives them an anecdote to tell to their friends and clients. Salinger is clearly targeting a well-bred audience. Further, what is said is more important than what is shown. The film's genius lies in the rich dialogue. Much of the film is conversation.
People talk at weddings, in restaurants, and during concert intermissions.
The society in which the tale is set is foreign to majority of the free world. You'd bet the persons that fill this film all subscribe to The New Yorker and read The Wall Street Journal during morning rush hour. The actors, however, are what makes the film succeed. Smith has range. Anyone who thinks otherwise will reconsider after viewing his mind-changing performance.