[YaesuSystemFusion] What does the HRI-200 actually do ?

I'm trying to work out what the HRI-200 is actually doing.

Fusion radios already contain a CPU, audio ADC/DAC's, a C4FM modem, AMBE+2 vocoder, a DSP (operating as the C4FM mode and vocoder) and a serial communications port for direct connection to a PC.

I could understand having a unit like the HRI-200 IF it had a network port on it that allowed it to act as a stand alone bridge between the radio and the Yaesu internet based network system. But no, a constantly connected and running PC is requi
red to act as the internet-interface/bridge/radio-controller etc, which of caused can already be plugged directly into the Fusion radio without the need of a seperate box (the HRI-200).

So what actually is the HRI-200's role in all this, what is it actually doing that the Fusion radio and PC alone couldn't already do as a pair ?