This is a significant moment in the novel for several reasons:
* It contradicts Elizabeth's previous assumptions: She had believed Darcy to be completely opposed to Lydia and Wickham's relationship.
* It demonstrates Darcy's change in attitude: His presence at the wedding shows that he has softened his stance towards Lydia, possibly due to his growing affection for Elizabeth.
* It hints at a deeper connection between Darcy and Elizabeth: The fact that he chose to attend such a scandalous event for Elizabeth's sake suggests that he cares for her deeply.
This surprising detail sets the stage for a reconciliation between Elizabeth and Darcy, leading to a happy ending for both.