Honestly, while there is satisfaction in the villain in a story who has caused so much harm and destruction to get that kind of death, I think there's just something about them getting such unexpected/simple (well... being struck by lightning isn't simple you get what I mean)/short deaths.
While on one hand people can say that it shows that they're humans at the end of the day (in most cases) and are like anyone else (*cough* something the harry potter movies messed up when converting the book into said movie *cough*), I think it's also like fate didn't even seem them worthy of giving them that kind of attention/time/effort, so it's satisfying as well in it's own way (it's like fate saying "I'm done with and your shit, however I don't deem you worthy enough to put any of my time and effort into making your end become a reality".
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And this is a spoiler for anyone who hasn't seen the movie "San Andres", but there's a character named Daniel who literally leaves his future step-daughter, Blake, trapped in a car to die in a parking garage as the building is collapsing around them (she gets out with help soon after), as well killing other people throughout the movie (like I get he was trying to save himself, but he didn't need to be dick and get other people killed in the process, essentially murdering at least one or two people). Then finally as he is trying to get across the bridge to safety, a tsunami occurs, picking up a cargo ship, which sends a huge shipping container to smack him in the face and it was so satisfying, ngl.
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Also, with having simpler deaths like that, I feel like at times it can be easier to tell if they're actually dead or not, or if they somehow got away since the other death is a lot longer, meaning more time to get away I feel (though none of this logic really matters in superhero worlds like Marvel or DCU).
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I have a spoiler as to what that fake saintress' death is going to be like, though I admit I'm not sure how long or painful it's going to be.
The fake saintress is consumed by Darkness and killed, bc she didn't keep up her side of the deal they made so that she could stay in power.
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Here's a more in depth explanation, but I have to tell some BIG spoilers to do so.
You know that hooded figure who promised to help her remain as the saintress and how she needed to hold up certain conditions? That's the main antagonist, Darkness (which is all evil and wants to destroy the world just because). One of those conditions is to keep her Wings (only 4 of them were actual Wings (3 being brainwashed) and the others being fake ones Darkness made (which includes the Wing with the scar on his face that's going to be coming up soon, his name starts with a T I think?). Well the 4 Wings goes to the actual saintress, while the others who weren't actually loyal and only sought greed left the fake saintress as she lost her power and/or were killed. So the Darkness basically tells her that she messed up and consumes her (the FL's brother was consumed by Darkness a long time ago and was essentially a puppet, I think he actually gets killed as well before this)

Y E S
Even though it's only a little for now the fact that the goddes threatened that stinky bitch gives me hapiness.