What this passage reveals about Daisy and Gatsby's relationship is the reason that Gatsby became obsessed with Daisy in the first place. Like many of the disenfranchised poor of the 1920's, Gatsby was bitterly resentful of his economic circumstance. He saw none of the vapid, materialistic, and futile existential quandaries that are so commonly associated with the American upper-crust. To Gatsby, there were two worlds: one that stayed exciting and beautiful and mysterious, always glamorous and youthful no matter how many years passed, and another where things were dirty, hot, and miserable, with all the excitement sucked out of everything. Gatsby believed that the only difference in these two worlds was money.
However, social norms dictated that simply having money wasn't enough. The money had to come from the right place. Gatsby was new and exciting to Daisy, but his status as new money made their relationship impossible. No matter how much money Gatsby made doing something like bootlegging, he could never truly be the glamorous, upper-crust socialite that he had dreamed of becoming because he had not been accepted into the culture of wealth as he perceived it. This is what Daisy ultimately represented to him. In Gatsby's mind, if he could just find a way to make Daisy his, he would finally arrive as the type of wealthy person that he had always dreamed of being.