My opinion is that the added value is not always a factor of 'quality' alone and can also be influenced by the viewer's relationship with the medium. My guess is that darkroom printers may value an original print more than, say, a layman who may find a print in a book perfectly acceptable, even identical. Likewise some people may be adverse to looking at photos on a computer screen - my elderly relatives can't stand doing that and are only interested in passing around 'real' prints.