Body & Engins block Ground

The video uses the engine as the primary ground. it also grounds the engine to the body, but never ground the efi to both the engine and the body at the same time. is this to minimize the potential of a short that could come from the body? Would the other reason be to isolate the ground to the engine only in case you have to diagnose a round issue?

We want to always use a star earthing point for our grounding as this can prevent potential issues due to ground offsets affecting sensor readings. Grounding the ECU to the chassis can also potentially damage the ECU in the event that a main power ground is damaged as the ECU can become the current path for high current loads.