They would also need some ATC management system for control of aircraft on the ground. It is easy enough to land in CatIII conditions but getting to and from the runway to the terminal safely can be a bigger problem to solve
There is nothing ATC can do to get you to the gate! They will not give you step by step guidance in Low Vis!
You are on your own I would suggest. Hence the min vis requirements for landing. You can land in zero vis., but you can't taxi!