To appreciate a photo without being distracted by how much it has suffered…
Until digital cameras were invented, photography was an expensive hobby, and even 2 generations ago, high quality professional portraits were luxuries that few could afford to have done regularly.
Most people therefore have just a few photos of their ancestors – these being the only images that will ever exist. Fortunately, despite the damage and degradation caused by the years, many such photos retain their inherent quality (sharpness and dynamic range), and respond well to restoration.