Help wiring Icepower amplifiers please

I used my multimeter to determine the ASP1000s' big aluminium heat shield base, is also the ground, AND the XLR ground pin, and AC earth pin are already grounded to this. So the amp should play with only the wires hooked up, and without a case.
     So why exactly would I care to make a star ground to the aluminum base plate of an aluminum enclosure, IF the amp is already grounded? 
Seems to me adding a star ground would be asking for ground loops, since the amp is already grounded.
      I am NOT using the DC bus out wiring to another amp module. As far as I can tell, the only connections I have to make is to hardwire the XLR connection cable to my own. Put an AC plug on the power cable. Hard wire my speaker cables to the plastic connector. And it should be fine. 
Please help me understand why I may want to add a ground to the chassis, when my grounded heat sink is screwed tightly to the aluminum chassis ? Thank you for helping me be safe.