Curious about this too, I have a stay booked with Amex Fine Hotels & Resorts and was wondering about the breakfast and $100 property credit. I tried emailing and calling but wasn't able to get hold of anyone which is to me already a bad sign. But I'm probably going to stay here since it's the lowest rate for FHR in San Francisco for the dates that I'm staying.

Edit: Finally got a hold of someone on the phone, the credit is for parking, in-room dining, the bar, and the Third Floor restaurant only. Cannot be used at Niku or anything on the ground floor. FHR breakfast is $60 at the Third Floor.