How does Jordan Baker impact the novel?

Jordan Baker is a professional golfer who cheated in order to win her first tournament. Jordan is extremely cynical, with a masculine, icy demeanor that Nick initially finds compelling. The two become briefly involved, but Jordan rejects him on the grounds that he is as corrupt and decadent as she is. I think Nick uses Jordan as sort of a barometer to guage just hoe vapid and negative East Egg Society is.