I find that the strength of existential arguments lies in the equally valid quality of other existential arguments.
For instance: a creationist is as justified in claiming a creator for the universe and the proponent of the Big Bang for his theory. The reason? There is an innate need to understand where everything came from. It is not about the evidence – that’s what evidential arguments are for.
So why does this equal justifiability give strength to existential arguments? Because the subjective nature of the human mind is satisfied. This will then drive evidential arguments toward validating the existential position.