Without assuming I have anything like an answer, here are some thoughts that came to mind on this topic. What if, the use of the term 'giants, ' is a way of confronting the fact that we, us ordinary humans, are, ourselves, best described, as 'puny.' A way, like looking at something in a reflection, of dealing with something that would be too crippling if directly confronted. And if my thoughts have any value, this line of reasoning suggests this use of mirrors to deal with dilemmas, is really basic in the human psyche.
One result of men thinking their survival depends on outwitting 'giants,' is that men are here grasping fundamentals of reality, whether their foes are giant, or they themselves, small and ineffective physically. To me it is obvious, men are, looking out at a starry sky, small in terms of what they can survey. It sometimes seems that this reality emphasizing perspective has been lost by many today, who see MEN as giants, that is people who are "on the verge of figuring out all of nature's secrets." One can wonder, surely, how realistic this shift is.