What is the importance of St. John the Divine Church in the memoir, The Year of Magical Thinking?

St. John the Divine Church is the setting for several key events in the author's life and recollection—Quintana's wedding, John's funeral, and her encounter with the Japanese tourists in the book's final chapter. In contrast with the sense of displacement she finds in New York Hospital, the author seems to find comfort in the familiarity of the church.