For me the radio is in the SENA 20 intercom we have.
FWIW, the availability of the intercom was what changed my lovely pillion from a reluctant participant to an advocate proactively suggesting we ride. That aspect of it: priceless.
Back to the radio - being able to scan for traffic (sometimes) and weather (more often) is the primary - exclusive ? - purpoe - and of course, being in the helmet, not subject anyone else.