Why star ground????

[glynster]

I am assembling my DIY electronics enclosure and wiring everything up and of course I have heard that star grounds are the best in this case. My case/box is perspex with a aluminium plate as a base to which all components (drivers, BOB, PSUs, etc) are connected.

It has me wondering, why trace all grounds back to a single star ground point when I could simply drill and ground into this aluminium plate multiple times locally (aluminium is high conductive after all) and then connect the earth lead to the ground plate also? The entire base of the case would then be one common ground which in turn is then connected to Earth?

Also, I am confused about what components need grounding to the chassis/star point since some seem to be acting as the neutral although they are labelled as ground? For example, I have the KK01 BOB from CNC4YOU - do I ground that?

Sorry if this is a rookie question - I couldn't find a specific answer in search.