Advantages of radio firing: no flash affecting the scene, no need for "visible contact", prevent "strangers" firing your flash(s) or someone else's flash(s), sure firing even in the daytime.
Conversely, the launcher/trigger allows e.g. two f
Servo trigger
Allows multiple flashes to be fired simultaneously, cable-free, using an electrical sensor that monitors the flash of the master flash.
Aftermarket.