I disagree that there is only one impulse which leads to Christianity, or any other religion. There are many reasons people would want to believe any of the vast range of things which are collectively called Christianity, ranging from the desire for transcendence that you mention to a deep self-loathing which needs some form of relief in a faith which claims it knows how an inherently evil humanity can be redeemed of its evil. What one's reasons are for going in have a deep effect on what form one's belief takes and what one gets out of it. Your description is indeed one motive for being a Christian; it's far from the only one. And I think people who have it in them to be great writers, painters, thinkers, etc. will find their own motivation. I don't think Christianity is a bad inspiration for such, only that it's not an essential one; anything which sparks the human imagination will do the same job.

What Christianity does do is a bang-up job of sparking the human imagination. Depending on whose imagination and what they imagine, this can lead to glorious works of art, or Crusades and witch-hangings. I don't consider it either inherently a good force or a bad force, only a force in the mind that is molded by what mind it occupies, and what is already there.