Is it possible that there is a part of us that reaches beyond our base natures, to reach for that which is bigger than ourselves?
I'd say there seems to be a psych need to know our place, within society and our place in the "big picture". We are social animals at a base level. Animals seem to both instintively know and learn their social status; fear of predators and knowing what to eat is innate, pecking order requires some challenge and contest. Perhaps taking on the god/father archetype is nothing more than challenging fate for dominance of our own destiny. Perhaps not.
However, not knowing if dolphins think about water, air and things beyond fish, I'd say most if not all of us confront the god question at some point or other. Where did we come from? What is my purpose? Is there something beyond this life? I think any sentient and rational being would have to derive an answer one way or another. It seems there is little question to the diversity of the answers and all are true it seems. Our nature is not absolute or universal, thus it may follow that neither are our beliefs and "truths".
Is believing in god helpful? If it gives someone peace, how could it not be? Of this there is ample testimony.
It can also be said that not believing in god is helpful and there is much evidence of this.
Is believing in god more helpful (or harmful) than not believing?
It's a divide by zero question, undefinable and has no answer ;)