I think it's more advertising for Patek in general. The handful of people who have both the means and desire to purchase such an object likely got informed by their personal networks long ago. But Patek wants to sell $20k Calatravas to merely affluent people who want "the best watch" and this piece helps position the brand. I'd not be surprised if there was significant PR effort from Patek behind the scenes on this one.

For something that's expected to sell for over $10m, I doubt they figured one internet article would surely help sell it. I'm fairly confident anyone who seriously wants to buy one of these already knows it's up for auction.