I have more faith in the durability of these ads than app install ads. What they are selling here are campaigns that are backed up by results (whether control exposed or pre-post studies):
For well over a year, Facebook has invested heavily in products and analysis to better understand what happens after it serves an ad. As a result, the number of ads served in the fourth quarter is down 65%. But the average price per ad is up a whopping 335%, according to the company’s finance chief.