Of the many things that are all too commonly misconstrued about Celestia Ludenberg, I feel we don't talk enough about her "dream". People usually miss the whole point of that, mainly because they're taking her words (words from the Queen of Liars) at face value and Kodaka made the dumbass choice of including silly music in the scene where she's talking about it (like much in that chapter, the anime did it better because it had sad music...since it's sad.)
Celeste's words to describe it are living in a fancy European castle like a princess where she is served by handsome men dressed as vampires and spends every day "worshipping the aesthetic decadence" around her, so taken at value she just comes off as a shallow bitch who just wants to live for material and sexual pleasure, and would even kill for it. However...
1.) If you've done her FTEs, it is made incredibly obvious that Celestia Ludenberg is a false persona Taeko Yasuhiro crafted for herself based on manga. And manga/anime protagonists will usually have these big, outlandish and often self-centered dreams as motivations. Become a Pokémon Master, become King of the Pirates, become Hokage, become the World's Greatest Hero, become God of a New World, earn enough money to get something important, overturn the established order to create something better, get revenge on someone who wronged you, discover paradise or the secrets of the universe...you get the idea. Celeste's "dream" is her character motivation. It's not what Taeko actually wants: what she actually wants is just to live her life as Celeste and that's merely a justification for it. The selfish, greedy, materialistic aspects are all aspects of Celeste's character that Taeko made, and she is speaking as that character in the moment where she describes it, not as herself.
2.) When you take Taeko into consideration and imagine how it would be if she ever achieved the "dream", it's both incredibly sad yet also incredibly relatable. It's almost a form of suicide: Taeko gets buried for good and all of the wretched self-esteem that comes with her, and she can spend the rest of her life just imagining herself as Celeste and not truly living anymore. But while this is something unhealthy in how far it's taken, the impetus behind it is all too understandable, especially to autistic people like me: Taeko fears the "real world" because the "real world" has hurt her for just being herself. People were neglectful at best and hostile at worst toward her. It's made her want to escape the "real world" and live somewhere cozy where she feels safe and comfortable and valued. Again, GOD do I feel that, being autistic.
3.) The scene where Celeste describes her "dream", despite having a full CG illustration for it, isn't voice-acted. What is are her last words where she basically admits that she wouldn't have killed anyone if she had hope in Alter-Ego getting them all out of the school alive, meaning she would have foregone the money motive which exposes her "dream" as less important than she made it out to be. This is further reinforced when we find out that Taeko had actually given up on the "dream" to accept living in Hope's Peak Academy forever with her classmates during the Tragedy, and later Bonus Modes flesh out that the likely reason she could do this is because she came to like and trust her classmates, because they accommodated her on how she wanted to live her life and be perceived, and even supported her pursuing her "dream". She feels safe and comfortable around them; valued by them. It's why it's so damn despicable that Junko took that away from her, wiping her memories and making her view them with suspicion, distrust, and fear for her life and preferred existence.
Tl;dr: anything Celeste says about herself while "in-character" deserves this response:
