"Superchargers" are Tesla specific high speed (typically 120 kW or more) DC chargers, and not your typical J1772. So not compatible with the Volt in any way.
"Destination chargers" are lower power (20 kW or less) AC charging stations at hotels, motels, and other points of interest. They are J1772 in electrical protocol, but have the Tesla specific plug on the end. One could actually hack off the plug and use a J1772 plug, and it would work fine with a Volt. In fact one outfit is in the process of making adapters available so J1772 cars can use Destination chargers.
Partly because Superchargers charge the cars so fast, they don't need to hang around for very long. But, I suspect, also partly because the Supercharging network hasn't supported travel westward across Iowa - until the very recent installs in the QC (Davenport), Iowa City, and Des Moines. With these latter Superchargers in place, I think Aurora will start to see a lot more use.