IT makes them sound more importatant to those who just see a guy untagleing ropes. And it helps to justify the purchase in their mind.
If I remeber correctly the highest price ever paid for a 'photograph' was about 2.4 million at a Southerby's auction. Was some picture from the turn of the century on long island, NY, showing a hazy shape of the moon shining thru some trees. Course if you put that in perspective with the highest 'paintings' have gone for, 1 mil and above is not that common to see for just a photograph.