He not only shrouded the spice in ritual and religion (which isn't THAT suprising considering many human societies used visionary substsances, and Herbert was a child of the 1960s psychedelic culture too) but also give it a central place in the economy and functioning of the empire.
What if a visionary substance was the real deal that gave you insight and precognition? What a rebel leader took full advantage of such a substance? What if that was combined with religious fervour?
Dune is basically space war + outsider Messiah + Islam + psychedelics