for doubt and secrecy are the lure of lures, and no new horror can be more terrible than the daily torture of the commonplace. - H. P. Lovecraft

No new horror can be more terrible than the daily torture of the commonplace.

Religion is still useful among the herd - that it helps their orderly conduct as nothing else could. The crude human animal is in-eradicably superstitious, and there is every biological reason why they should be.
Take away his Christian god and saints, and he will worship something else...

What it is, only God knows. In terms of matter I suppose the thing Ammi described would be called a gas, but this gas obeyed the laws that are not of our cosmos. This was no fruit of such worlds and suns as shine on the telescopes and photographic plates of our observatories. This was no breath from the skies whose motions and dimensions our astronomers measure or deem too vast to measure. It was just a colour out of space — a frightful messenger from unformed realms of infinity beyond all Nature as we know it; from realms whose mere existence stuns the brain and numbs us with the black extra-cosmic gulfs it throws open before our frenzied eyes.

It is well to avoid actually recognized myths such as vampirism, reincarnation, etc., and invent one’s own obscure violations of cosmic law. What common myth, for example, does Blackwood use in The Willows? Or Chambers in "The Yellow Sign"? Or Hodgson in The House on the Borderland? These writers create a sort of distinctive awe of their own and manage to say something fresh despite all that has been said before.