China and her carrier

Thornton
Many questions have been raised regarding China and the possibility of the PLN to field a carrier (such as the “Varyag”)in the not to distant future. Given Chinas vast land mass and extensive coastal air bases which stretch from the Yellow Sea to the Gulf of Tongkin, what possible use would the PLN have for such an vessel? Okay, force projection is an obvious use I grant you, but facing a force such as the U.S. with its superior number and fire power or Japan with its excellent Navy – could it survive? The Eastern seaboard of Taiwan is already within striking distance of PLA Su-27 aircraft and JH-7 strikers – so the carriers use to attack Eastern Taiwan is pointless.
The only real use for the carrier would be as an emergency airfield, such as if the U.S. was to launch a large scale cruise missile attack on Chinas airfields. I may of course be wrong about this. Anyone got an opinion?