Make-believe intended to scare people into accepting their bad lot in life.
I wouldn't say it's strictly for the purpose of making people accept the hand they were dealt even if it's a shitty one or to scare them into not committing suicide. I think it could just as easily be a mere observation of the fact that a suicidal person is
already suffering endlessly. I'm not really familiar with Korean religion/superstition but iirc it's traditional religion was Shamanism which I remember hearing is similar to Shinto and I think both of these basically dictate that the way in which a human spends their living life is reflective of how they will spend their after life (both don't really have concepts like heaven/hell but more like a separate spirit world and there's a lot of stuff about spirits still roaming the land of the living, especially in places that were relevant to them when they were alive) so if they spent their life suffering, their spirit will likely be a malignant one because of how their soul is still in a state of unrest. It's probably just genuine superstitious belief & concern. Religion, superstition, spiritualism - whatever it may be - I know all of it has an extensive history of being used as a means of controlling the population through fear so they will continue to obey the 'powers that be' but to label all of it as 'make-believe' or to even think that it was created with that sole purpose in mind is a little extreme (which, I'm not implying you are, I'm just going on a fun little tangent).
I personally find things like this super interesting, the concept of ghosts still roaming alongside the living albeit in their own dimension that is for the most part imperceptible to living souls with the exception of rare apparitions, or them 'haunting' the place where they died. Or even things like spirits being stuck in their past memories sort of locked in an endless loop of reliving the things they went through. It's strangely fascinating to me.
I assume OP is Korean and was probably raised by people who hold these beliefs so they're concerned that if they were to CTB they would end up in endless suffering whilst being cursed to haunt the place of their death, but I mean.. that's the thing with pretty much all of religious/superstitious belief. Nobody can really 'prove' or 'disprove' anything. Sure, someone can put on their reddit glasses and "ackchyually, science..." but I find views like that to be as obnoxious and ignorant as those who are militantly religious and refuse to step out of their doctrine for a single moment.
