I think the function will be very useful for rare collectors as well as genernal public. It doesn't have to be a in game function - player submit request asking the count of certain items, dev do a scan and tell us the result in FOF. Not only can it help us to value the in game items, it can also provide us early warning sign of "extra copies" of items emerging in the game. On a smaller scale, it would be nice to be able to search items in a player's house in game. Maybe a servant like the bar tender or assistant that can be placed inside the house. That would be great news for us less organized packrats.