I'm gonna use a Zero Wifi with a camera to monitor water consumption. Since I already have a mysensors network and mysensors can run on a raspberry pi, I might as well hook up a radio and transmit it on the sensor-network.
To answer my own question, looking at the code it looks like it will disable the gateway functionality. The "Starting gateway..." text doesn't look at the flags controlling the behavior. I haven't hooked up a radio to my pi yet, so I haven't verified it.