I got it too. Platinum status and just made Lifetime Platinum a couple of months ago. Used it at the Chicago O'Hare Marriott. At first, tried to use it to buy snacks in the shop next to the front desk. Couldn't do it -- computer said not valid. Then just credited to my folio and it worked fine.
I was surprised to receive it. The validity was one month from my birthday and fortunately already had a trip in that timeframe.