There is no way to either prove or disprove god.
E.G:
LOOK! This fact disproves god!
No it doesn't, it was put there by god as a test of faith.
or
LOOK! This fact proves god exists!
Erm, that fact needs more scientific study, I'm sure there's a logical explanation for it.
Actually, what you're presenting is more the idea of "the God of the gaps", i.e., anything that cannot be explained by current science is then pawned off on a higher being. Given enough time (read: if we don't blow ourselves up first), I think science will advance far enough to end what we know as traditional religion. I'd go so far as to say the only reason religion persists so strongly today is because of an ingrained ignorance and a nostalgia for tradition that permeates the political atmosphere.
But to your intended point, even if you consider religious debate fruitless, it is a forced necessity. Even if you can't say without certainty if a god exists, the fact remains that people have enough
conviction in their beliefs to
act on them. Let's not beat around the bush: religious zeal has a way of accompanying violence. Not one major world religion is free from fanaticism that results in the death of innocent people. If someone is willing to kill a complete stranger based on some conviction, isn't it natural to question the validity of that conviction?
Ignoring the violence issue, religion is an expression of some fundamental dimension of our humanity. Humans have always asked why they are here and what their purpose is. This impulse is what Tillich called our "ultimate concern", because how you answer these questions will dictate how you live your life (refusal to confront the questions is an implicit answer itself). The traditions of religion are a very mainstream outlet for this impulse, but we must each answer it for ourselves. Thus, although we may never be able to say if god exists or not, the question (and debate) is inevitable.