When roaming, it is useful to know what actual carrier is in use. The “Router Utility” app on the iPhone actually shows this information, but the router’s Web UI does not.
We use this information when using SIMs that support roaming, so as to know which carriers are covering remote areas and to ensure we don’t wind up with two SIMs in the Transit Duo both roaming to the same roaming carrier and thus having less redundancy.