New to this so thank you in advance for putting up with this question.

Wiring a Jamma Harness for a new 60-1 PCB to a Happ Switching power supply. I have all the DC grounded back to Logic Ground at the DC power source. I'm assuming the earth ground at the power supply is for looping all the metal parts of the cabinet? Or just a convenience to ground the power supply itself? I've already grounded the power supply back to earth ground. Just afraid to flip the switch and see this baby run. Thanks.