I think it's too much of a stretch to label anything "irrational" as superstition.
I think both the purported benefits of the shareholder-theory-of-value and fictionalization rely on plausible-but-false belief in the outcomes created by the 'invisible hand'/selfishness-at-scale, but I wouldn't call it superstition, just wrong.
Also, I think the connotations of words are pretty important, and there are a lot of words that for the most part mean the same thing with different connotations. If I had to describe the connotation of superstition, its an action believed to have an effect, but that effect is a total non-sequitur. At least with what we're talking about, there's at least a plausible basis for believing the effect will happen, even it that basis is wrong.
As economist Stevie Wonder once said, "When you believe in things that you don't understand Then you suffer Superstition ain't the way"