I just received my AmEx Platinum last month in order to take advantage of the 50k MR promo, but after only 2 weeks of using it, saw it's value.
We were headed back BOS-RDU on Marathon Monday, when our flight had a fault and was cancelled. As I'm only FO on Delta this year, the other PM's and GM's were rebooked direct but not so lucky for me, I was placed on standby and with the crowd behind me also trying to figure it out, I went to the Sky Club and handed her my card. The lady took my tickets, assured me it would be a small chance I would get a seat on the next direct flight as there were so many standing by, and instead booked me on a flight with one connection that got us into RDU 5 hours later, but was confirmed. After that, and the open bar we had while waiting there, the $450 fee seemed minimal.