Love your Nautilus, though if I'm not mistaken, it's quite possible to get the solid gold models at authorized dealers, and probably the stainless steel chronos. The stainless steel time/date watch is very difficult to obtain. Of course, it doesn't mean your model isn't nicer (I think it is). I heard all list prices on these are going up 20% on March 1.

My own opinion is that AMEX "follows the money" and doesn't really care whether you buy particular luxury items at particular dealers. Perhaps they use it as indicia you have large disposable income and you will be an ongoing profitable customer. They make good money on luxury travel you book with them (air, but more so, cruises and land tours) and my guess is that type of spend would put you on a faster path to get this card.