I find that the questionable nature of Nostradamus' predictions--the way they are vague, cryptic, and indiscernable, almost of no use to anyone in the present--these things show the murky manner and odd origin of his prophetic conclusions.
God is clear. God gives promises. His light pierces the cloudy fog that Nostradamus' prophecies thrive in. Holy prophecies are clear as day, and they come true.
Nostradamus is fun and all. His red comet prophecies are startling. Perhaps there's truth in his predictions. But he's not too reliable. If you read him, take him with a grain of salt!
As for Dupont: I, too, would like to know more about why he made the choice of including Nostradamus in his book.