Answer:
Chopin makes a point of mentioning this because it is while she is looking out the window that Mrs Mallard has an epiphany.
Explanation:
In Kate Chopin's "The Story of an Hour", the main character Mrs Mallard has a heart condition that may kill her in case she gets shocked or surprised by something. Her sister and a friend are, for that reason, very careful when letting her know that, according to a couple of sources, Mr Mallard has died.
Mrs Mallard then locks herself up in her room and cries for a long time. But while looking out the window, she can't help being taken over by a sudden feeling of freedom. Through the window, there is a whole world that hasn't stopped living, working, pulsing, because of her husband's death. And she realizes she is as alive as the world is. From now on, even though she did love her husband and was loved by him, she knows she'll make her own choices; she'll have no one to answer to.
That is why the author makes a point of telling the reader about the open window: because it is while she is looking out the window that Mrs Mallard has an epiphany.
