It's a city simulator, not specific city simulator or even close. It is not accurate either as accuracy was not the main goal, but fun.

Human brain is a very specific and complex brain which we do not understand - vastly less than even cities at any scale. And to produce any useful answers, the model has to be accurate to some degree - and we don't know how much. HBP indeed had no question which it tried to answer - it's more like climbing a mountain because it exists.