In the occult sphere, there's varying degrees of belief. Some people just RP, some people this stupid half ass "haha it's psychological, they aren't really demons but subconsciously things happen in my mind!" thing, some people literally do drugs and radically shift their beliefs as a form of practice, and then there's good old fashioned "the universe follows principles beyond the ken of man" occultists that unironically practice magic and expect real world results.
Certainly, old grimoires were written by those of the last mindset. It's hard to say which is the most popular, occult circles have unpleasant overlap with mentally ill people deluded into believing they have special powers, new age cafeteria Christians who don't believe in much of anything, spiritually lost fellows not sure what to believe, and role playing fans who don't realize other people are serious. That isn't to say that anyone who things they have special powers is whacko by the way, but it is to say that an awful lot of schizophrenic dudes with hypergraphia will happily tell you they're the chosen embodiment of Metatron here to save humanity from the Zionist New World Order and have written "proof."
Anyways, what I'm saying is despite being into that stuff I have no fucking idea. On reddit the psychological perspective is very common, in too much free time Florida house wife new age groups christianity + karma stuff is more common, etc. Given the subject in question is defined by being hidden, I don't think a thorough enough survey to determine wide scale demographics of belief is feasible.
Damn I made a lot of run on sentences...