That is a perceptive distinction: Satan as theology versus Satan as literature. The literary figure has often become far more psychologically interesting than the doctrinal one.
Historically, the horned, hoofed devil is itself a kind of cultural collage. Medieval Christianity borrowed visual cues from pagan nature gods—especially figures like Pan—to make evil visible and memorable. Horns, hooves, tails: these were symbolic shorthand, useful for sermons and art aimed at largely illiterate populations. The devil had to be recognizable at a glance.
But by the nineteenth century, especially in Victorian and Romantic literature, Satan becomes subtler and psychologically dangerous. He stops merely tempting gluttony or drunkenness and instead aims at vanity, genius, ambition, wounded pride, loneliness, forbidden knowledge. That fits a more educated culture increasingly interested in the inner life. One thinks of Faust, where the devilish figure appeals to intellect and dissatisfaction, or The Picture of Dorian Gray, where corruption works through vanity and aesthetic temptation. Even in earlier works like Paradise Lost, Satan is compelling precisely because he is intelligent, eloquent, proud, and tragically self-justifying. John Milton arguably made Satan too charismatic for orthodox comfort.
There is also something psychologically true in the literary Satan selecting “desirable souls,” as you put it. A dull temptation story is not very interesting. Literature gravitates toward protagonists whose strengths are entangled with their vulnerabilities: the brilliant scholar tempted by knowledge, the idealist by power, the virtuous person by pride in virtue. In narrative terms, temptation works best when it amplifies something already present rather than introducing evil from nowhere.
From a secular perspective, one can read Satan as an externalization of inner conflict: ambition against conscience, appetite against restraint, ego against humility. In that sense, “the devil” becomes a language for the parts of ourselves we half-recognize and half-disown. That literary move survives even among people who do not believe in a literal devil.
At the same time, I can see why the nun-school version you described earlier would invite ridicule, especially if Satan is presented as an invisible cosmic peeping-Tom obsessively monitoring adolescent behavior. For many people, the symbolism became flattened into something oddly bureaucratic and moralizing.
Yet the symbol itself has remarkable staying power. Human beings seem to keep reinventing some figure who whispers, “You deserve more,” or “Just this once,” or perhaps most dangerously, “The rules do not apply to you.” Whether one calls that Satan, temptation, ego, shadow, or simply human nature depends very much on one’s framework.