What purpose does the newspaper boy serve? Why does Blanche kiss him?

The scene with the paperboy exposes Blanche's delusion. She doesn't appear to be a predator as she flirts with him, but rather, she appears as sad and pathetic. Blanche is drawn to children, children who are innocent and gay, as she imagines herself to be. Trapped emotionally in a fictional past – was her childhood so innocent with the epic fornications of her family, or her youthful love so pure with her "degenerate" husband? - she grasps at the straws of youth that she sees in the paperboy and countless other youths before him.