I have seen multiple match cuts in Bad Times at the El Royale (2018).
This is one of the match cut used in the movie:
What is the significance of these multiple match cuts?
In this specific case, I would say it is to show what the girl actually become. More precisely: how she feels about the deed she committed. Hanging by the fire doesn't need much details, she is careless and even infantile, enjoying a simple thing like fireplace. Same look in her eyes and behaving after their victims shows she doesn't feel remorse, actually looks on it like a game, like playing with dolls. This is confirmed when cult leader says to her older sister about dealing with what girl has done, and girl reacts with "What have I done?" like getting angry for being falsely accused, before her ratio kicks in so she has to acknowledge she did something.
* small spoilers ahead *
Also, this is continuation of previous flashback when sisters were young and older sister protected her by taking the violence herself while little sister stays under the bad. However, we are shown that she stops being afraid and has positive look in her eyes, as obviously her way of adapting to situation. So she becomes deranged in this way. Her sister can't accept it and wants to blame it on the cult leader, while cult leader is shocked himself with the deed. Match cut is the end and conclusion on what is she like about committing a murder.