Well, immediately afterward Grindelwald made the point of how long would it be before Muggles turned their weapons on wizardkind and waged war on them. I think the showing of WWII was meant to provide evidence of how barbaric and violent Muggles were and provide justification for attacking them first. It has been pointed out in the series before that generally wizards underestimate how capable Muggles can be, and that their stubbornness and refusal to use Muggle technology leads to them not being aware that Muggles can do a lot of things better with it than magic can (like communication). Showing stuff like tanks and nuclear weapons then ends up being a harsh reminder that Muggles are more dangerous and threatening than they assumed they were. ---
Okay, I rolled a 14. What's that mean? Hsu That you're a cheater. This is a 12-sided die. Chan