There are those who practice these things, believing that ~they~ have “powers” when in reality, they are in league with demons and the devil, who assist them with their evil “prayers”.
Yes, it is as real as the powers of angels.
Well, I don’t believe in ‘demons and devil’. (I think the key word in your post is ‘believe’.)
I don’t allow any power in my own ‘belief’ for idiots who ‘believe’ they are summoning ‘demons’. At best, they are laughably deluded; at worst, insane.