the first scene depicts that She was still Sparkle using a mask to perform. The second scene depicts that the mask has become her. The third depicts that the character she was performing has been given life thus controlling her.
“When I realize that life is just a play.” She said that because she learnd something about the reality of the world/universe back then, and that's when she decided or became one of the Mask Fools. We know Penacony is a dream world, and from the player's perspective we know the whole honkai star rail world is a game (kind of a dream world by its nature). What if some of the characters in the game also knows this? What will they do? Why is this important? Remember how Kafka mentioned about Elio knows about the "fate" or "script" of the world? Remember how Sampo seemed break the fourth wall and speak directly to us players? This is where everything becomes interesting. When we make a choice of the dialogue in the game, why do some of us always choose the one that is unhinged? Because we know that all of it is "just a play". "Why so serious?" Sometimes we can be the Mask Fools ourselves. At last, all about sparkle seems make sense now. This also fits how those in the Stelleron Hunters do when they are in a mission. Just like us players, they show little or no sympathy towards the enemies they killed, even if they are not monsters but actual humans. Because we know this is "just a play".
It’s like Furina if she didn’t have anything to fight for. The only way Furina was able to keep going was because she wanted to save the people of Fontaine. Sparkle in the other hand seems to just be suffering
I also get the vibe of Nahida’s “happy birthday” trailer where it almost feels like a samsara with the reiterating but this time the person has completely lost their mind and succumbed to the madness.
