Probably to mask the scandals that President Chen is in currently, but such an exercise could be useful as practice and to show the PRC that Taiwan can fight.
My dad was there in the South China Sea in 1957/1958 aboard the USS Hancock, to keep the commies at bay. His picture in the ship's cruise book shows him supervising the loading of an atomic bomb aboard an attack plane headed out on routine patrol. Back then the US planes carried live nukes on routine patrol, and the pilots received a target briefing before launch just in case the balloon went up. This was back when Red China was shelling Formosa (Taiwan) to the tune of 50,000 artillery rounds a day.