Well, I think it would be a waste of money to have just one 003. Since China already sunk money into the carrier reactor as per what VESSEL has said, this would mean that China will eventually develop and put into commission a class of nuclear-powered carrier. I think we can at least agree on the fact that China will have a functional carrier force. In my opinion a Chinese functional carrier force would consist of at the very least 3 catapult-equipped aircraft carrier, eventually nuclear-powered, this is to ensure having at least one carrier on active combat duty at all time.
However, unlike other ships, carriers are ships that rely on their onboard aviation fleet to produce real combat capabilities. Sure you can say that China shouldn't waste money on conventional carriers if she is eventually working towards nuclear-powered carriers. But the problem with this is that the combat capabilities of the ship-borne aviation fleets also needs time for build-up, training, and developing. If China wait upon the nuclear-powered ships, it would mean that she will have to wait until late 2030s at the earliest in order to have a fully combat capable (multi-) carrier fleet. This would be a huge waste of time.
Building at least a couple more conventional carriers like the 003, would give China the ability to develop a large and robust catapult-launched carrier aviation fleet to rotate duty, as well as developing and experimenting on multi-carrier combat group's fighting capabilities, organizations, and other processes. All of which can simply be readily transferred onto the new nuclear-powered ships once they are ready.
After all, carrier are just an naval aviation platforms. It is not the carrier themselves that fight. It's the naval aviation groups carried on-board the carrier that does the fighting. Having those platforms ready earlier is essential in the process of developing the capabilities of those naval aviation groups, even if those platforms themselves are not the most ideal platforms.
