I'm reminded of the difference between a fairy tale and an oilfield (or cowboy, or fisherman) story: a fairy tale starts with "Once upon a time..." and an oilfield story with "Now this ain't no shit...."
Religion/God stories tend to start with a prettified version of the latter.
....while there are not a lot of intellectually mature people who are fairy-ists.
In 2007 in the industrialized world, yes. 2200 years ago in Britain it's quite possible that nearly all of the intellectually mature people were fairy-ists. Bunches of God-ists today view the half-billion Hindus in India as fairy-ists of some stripe. And all those folks had/have the same amount of evidence for their fairies as Christians do for their uber-fairy.
That way, god has more evidence than the fairies and then you have your difference.
Again, that's in 2007. In Celtic Britain, there was plenty of evidence for fairies and none for YHWH. Cows dried up due to mischievious fairies. Old folks suffered "elf-stroke," now known as just "a stroke." The little buggers were everywhere!