User blog:Unicorn22/Explain Nicolas Flamel’s plot relevance in Fantastic Beasts 2

Toward the end of Fantasic Beasts 2, we see Nicolas Flamel. He was called on to stop Grindelwald from destroying a Parisian graveyard, but when he gets there he does nothing. Right after he gets there, we go to the adult Newt Scamander & Friends Hogwarts scenes.

So please,can anyone explain why we just reintroduce an old character and when their time to do something important comes, we skip to a new setting?