Celebrity owners would have got a brief sparkle from it. Perhaps also some of Apple's marketing budget too. And they continue to own a legacy item which will have notoriety beyond mere function.
Collectors of rare historical firearms presumably don't actually fire them.
I also suspect that given enough time those are the watches that will become collectors' items and will sell for multiple times their original cost so it's not a total loss for the buyers.
Yeah, like with high fashion, Chanel's runway show is there to make sure people come to buy the perfume, the only high margin thing they sell. It never made a ton of sense with Apple because they're like Warhol's thing about Coke: there is no luxury Coca-Cola; everyone gets the same product because it's the best. Similarly, there's no better phone or smartwatch than the highest end made by the mass market companies.