I am following the steps to have prod certs at IoT Edge Device using doc "https://learn.microsoft.com/en-us/azure/iot-edge/how-to-manage-device-certificates?view=iotedge-2020-11" and in my use case I am not setting up Edge device as the gateway. So in this case the tls connection will be between what and for what purpose these certs will be consumed ??
From the Microsoft docs:
These verifications enable a TLS (transport layer security) secure connection between the runtime, the modules, and the IoT devices.
In your case, you're not securing the connection with other IoT devices. The certificates are still used to secure the connection between the runtime and the modules. You can find more information about this certificate and the way it's used here