It should also be noted that the ad for the watch is not there davka to get people to spend that kind of money on a watch. If the advertiser is the one I think it is, that store is upscale, but has plenty of items that are affordable for special occasions (ie chassune, vort).
First of all, the watch manufacturer picks up some of the cost of that ad, saving the owner of the store money. Then, the watch creates an image for the store by letting potential customers know that the store is respected enough to carry such watches.