FWIW, I had gotten a Hilton Optima card but had never used it, and essentially lost in one of my drawers. When COSTCO no longer honored Discover, I couldn't find the Optima card and applied for a COSTCO/AMEX card. A few weeks later, I got a letter which said that AMEX could not extend my credit any further and rejected my application. When I called and explained the situation, AMEX said they would send me a new Hilton American Express - with a credit limit of over $30K!

I just got a flyer in my statement saying that they are upgrading my card to Platinum - not bad for a free card.

Now I can get into the President's, Admiral, etc. clubs when I fly.