An original photographic print (meaning one printed directly off of the film used to take the picture, not a copy) is the photography equivalent of an original painting.

With analog processes, half the creative work is in the printing process. If any post work was done, these prints would have been what other copies were made from.

Same reason why you'll see original prints from Ansel Adams sell for unbelievable sums of money despite there being better looking modern prints of his work available. You'd be buying the physical object that the artist spent hours fine tuning, the actual original which all other prints copied - and keeping in mind the darkroom printing process is what inspired the modern photo editing platforms Lightroom, Photoshop, etc.