Postcards like this one were at the height of their popularity around this time. This particular postcard was obviously used to demonstrate the natural beauty of the Palouse, as represented by the falls. Maybe these images even attracted other settlers to come out West and settle the region as well.

Image courtesy of Whitman County Rural Heritage. http://www.washingtonruralheritage.org/cdm/singleitem/collection/whitman/id/2737/rec/1