I was thinking of Lizzie's analysis of the situation in her letter to Mrs. Gardiner, about Wickham's turning away from herself and other girls and focusing his attention to Miss King:

"Kitty and Lydia take his defection much more to heart than I do. They are young in the ways of the world, and not yet open to the mortifying conviction that handsome young men must have something to live on as well as the plain."

I think Wickham's handsome looks are very important, maybe the most important thing about him; his looks are one of his main social assets and also as we see here they shape how others judge his actions.