I have availed myself of this benefit many times at offshore FS Marriott and Ren properties, and have never had a problem. Its a convenient way to get cash in a local currency. True, the exchange might not be favorable, but at the same time you don't have to worry about the undisclosed exchange rate at an ATM, or that applied by a credit card issuer, in addition to the now standard three percent exchange fee tacked onto your credit card bill.
Domestically, if you approach the front desk at 2:00 AM or so, and ask to cash a $500.00 check, the one clerk on duty might not have the cash in his bank to cash your check, and might not have access to added currency until the morning.
During the more active part of the day, I would expect that they would make a good faith effort to handle the transaction, without any quibbling.
Also, I have lower level of expectations when I stay at the other brands (RI, CY & FI) about the realistic value of Plat benefits. Thus, I am seldom disappointed with the way I am greeted at these lower end properties.