Alternative interpretation: Getting turned into a Dragon didn’t make her NOT the Element of Magic, and given G4 Spike’s mail-breath, not to mention the variety of alternative breath weapons the G5 Dragons could do in addition to all of them being able to do fire…
She can breath fire on a book to magically read the whole thing at once without harming the book.
Now we know what happens when Twilight Sparkle reads Twilight.
Yeah, probably not a good read.
Then, that doesn’t seem like a good read, judging by her face.