I used the benefit at the HR Hong Kong TST this past summer for a 6 day booking I made for my wife's sister. It was a great deal. I had booked them a room with my corp rate which was substantially cheaper than the daily rate, and then called back a few weeks later and upgraded them using points (I was feeling particularly generous).

The agent noticed that the daily rate was now cheaper by ~$20usd a day so she dropped the rate, and upgraded it to a suite with the 6k points.