Seems nonsensical that a Shaivist would convert a Sunni with a cosmological argument, for example. Cosmological (and other popular apologist) arguments largely cater to existing religious believers as confirmation (bias) anyway, as indicated by the gap from typical apologist arguments to the common elaborate religions. — jorndoe
I think these arguments serve two purposes:
1. reinforcing the beliefs of the already initiated, and
2. planting the idea of belief in those who are not
From the perspective of the faithful, these are positive. In a crisis of faith, having that rational justification can be reassuring. And while these arguments may not convert by themselves, they may at least lend credibility to the faith, which can later blossom into a conversion.
From the perspective of the skeptical, they are negative. These arguments are ad hoc
justifications for positions that are otherwise indefensible, akin to someone desperately clutching to whatever makeshift device that keeps them afloat. And they are dangerous too; otherwise level-headed people get hoodwinked into believing nonsense by a pretense of reason.
I have read many arguments for and against the existence of god. Each one of them seemed to me laborious, and driven by ulterior/subconscious motives. I have yet to read one that did not seem to be an expression of the person articulating it. I do not think that the question of god is something that can be answered definitely, one way or another, though I find myself leaning towards the skeptical end.