Worth it, if you want to visit Macau during your two transits.
Hotels are cheaper in Macau than HK (which would likely cover your ferry tickets), and with your noon time departure from HKG on your second stay, you can take ferry direct from Macau to HKG and then onto your US bound flight.
So, stay in HK for the first transit. On your second transit, stay in HK for first night, then go to Macau during the next day.