All other stringed instruments press down or against the soundboard, usually by passing over a bridge. Early harps are those that were built before the present century. Relatively few actual early harps survive, so replicas or reconstructions of early types of harps are referred to as early harps. More information can be found here . The study of historical harps appeals on a number of different levels.
Harps are visually interesting.
There is symbolism which comes from the uses to which harps have historically been set. The music of specific times and places is better understood when rendered on the instrument for which it was composed. Playing the harp with appropriate techniques can take you into the aesthetic of those times and places. All of this is a search for understanding. Be sure to include information about any harps that you own and whether you are a teacher, student, performer, researcher, or simply want to know more about early harps.