I'm actually confused as to why people surprised by those photographic panels, even going so far as calling the author lazy.
Don't get me wrong, this is indeed a creepy and cringy chapter (in a good way) but did you paying attention to the manga at all?
I remember that it was a major revelation back when chapter 216 comes out, so it shouldn't be a surprise to see that our world is the Fire Force world before the previous Cataclysm