Depleting anti tank missiles stock pile with drones could be a thing, but to bring these tanks in number on the battlefronts take time and crucial place of manned ones. But having some of these in front of manned tanks against antitank mine or ambush could be good.
Agree with your statement as a test platform. I think most people don't realize how expensive it is to convert old systems compared to building it brand new. With the old conversion there are a lot of physical limitations and workarounds needed that could impede tests. Would because everything is known about the old system, testing new technology on it gives you a good idea of the baseline and improvements of the tech.I really don't see this as an indication that PLA is looking to convert masses of obsolete Type-69s into unmanned vehicles. I think they are merely using a Type-69 to develop and test out their remote control hardware and software in preparation for future unmanned platforms. It's much more expensive to pull a Type-99 or Type-96 from an active brigade for this purpose or to build a specialized platform just to test out some electronics and software. It's simply overkill. The Chinese military is known for using obsolete/reserve platforms to research and develop new-fangled future tech.