Please help with homework Pride and Prejudice: Many of the important plot turns happen through

Many of the important plot turns happen through letters. A letter from Miss Bingley tells Jane that Bingley is gone for good and is supposed to marry Miss Darcy; a letter from Darcy fills Elizabeth and the reader in on the truth about wicked Wickham and lets her draw some new conclusions about him. Why does this information travel through letters? Could it have been revealed face-to-face? Why or why not?