We'll find out when the movie comes out. But many anime and and manga series have deliberately vague and misleading endings, which totally leaves the interpretation of what actually happened up to the reader. It's fun to pick apart what is given and try to see what is happening underneath what is shown.
I'm thinking of the end of a lot of the Ikuhara works, like Utena or Mawaru Penguin Drum. What we see at the end of both series is a metaphor for the events. Evangelion has had its ending written and rewritten multiple times, and all versions are canon in their own universes. The Tenchi series, too.
Are we delusional? It's a work of fiction. We're allowed to poke it and explore it and discuss it with the understanding that it's fiction. (Heck, you can get a college degree in doing that. Someone who studies pop culture is going to get a master's thesis out of this ending, I guarantee it. My husband the fan academic is already frantically taking notes over the reactions of fans...)