Yeah, I had seen that but it doesnt really explain why mine has an earthÂ*
electrode and none of the new ones do.Â*

Without being there to actually see it I recall there were a few burners that employed the same electrode as both ignition (arc) electrode and flame sense electrode. I can see the earth electrode having a purpose in positioning one end of the ignition arc. For the newer models it may be that reality proved that refinement unnecessary.