The gallery is a French Louisiana architectural adaptation to the heat of New Orleans.  Along with balconies and courtyards, galleries were living spaces, used as a respite from the closeness of the house.  People moved furniture outside and read, wrote letters, ate, chatted, etc. 

The gallery is transitional space, where the main house meets the workspace, and as such would have often been very busy.  The lady of the house might have spent a lot of time out here supervising the enslaved workers, who were cooking, gardening, and washing clothes.  She could also meet with vendors, who would have entered the property from the Conti Street entrance, and she would have been available to open the storeroom, in order to dole out provisions.