I disagree with the idea that knowledge of the occult can't help your game. One of the most fun things for me as a DM is designing plausible, interesting religions for my campaign world, and knowing a bit about diverse real-world religions helps me do this. My church of Mithra may be based in part off early-midireview Catholicism, but it still has a ritual in which new initiates crouch in a pit while a bull is sacrificed above them and they are bathed in the bull's blood.
And when I design evil crazy cultists, I take a page or two from Alistair Crowley. It's one thing to kill a cultist because she summons demons; it's another thing to kill a cultist because she captures poor people, drives them insane with drugs and spells, kills them, and renders their fat to make the ritual candles needed to summon demons, all based on a highly symbolic spell she discovered.
So no, I don't try to cast spells through my game. That is, of course, silliness. But I also don't mind using elements of real-world occultism to give the game verisimilitude.
Daniel