AC does not mean cooling. It means Air Conditioning, conditioning the air. In a car, where outside air is constantly being brought in, conditioning the air helps reduce mustiness from excess humidity even in cooler weather. In very hot humid weather, recirculating the interior air until most of the humidity is gone is best, again with AC on.
It’s very seldom that I turn off AC. You might do it when the outside air temp is in the low 70s and dry because sometimes the VW climate control has no idea what to do when the incoming air is the same as the inside desired temp. Sometimes that’s also a time to run recirc to prevent a strange smell from the confused system, or just open your windows and enjoy the fresh air.