It's probably an unhealthy mix of fiction and facts.
What goes for the 10 plagues of Egypt, science already got it covered. The rest of the story is more or less fiction, but I wouldn't doubt that in case the ten plagues really happened, there's no doubt that one would see a decent number of people, that would:
— use the ten plagues as a proof for existence of their god(s)
— use
FUD (it's super effective!) to gain control over
sheeppeople. (FUD tactics would take advantage of the ten plagues and the "this shit proves my god(s) is/are real" argument).