Fine, you want blunt? Let's do blunt.

Hermione is a dumb person's idea of a smart person (credit to Willie Donaldson)

The ability to mindlessly regurgitate facts is not intelligence. The ability to follow step by step instructions with more diligence than your peers is not intelligence. Being a biblophile is not intelligence. When someone says to me "I read x books a month" as though that makes them some kind of genius, I cannot roll my eyes hard enough.

Intelligence is, by definition, the ability to reason, to apply logic to a situation to achieve a desired end, to be creative and solve problems in novel ways. It is, basically, everything the twins are demonstrated to be good at. They're not knowledgeable, like Hermione, but if you put a rubix cube down in front of both of them I bet dollars to donuts the twins solve it before she does.

Hermione was not an idiot by any means, and even showed flashes of brilliance (ID-ing the werewolf curse, solving Snape's puzzle) but then so did Harry as the books went on, and neither of them hold a candle to the sheer insane genius the twins got up to - which we only even got to see a fraction of in the novels.

We all start off idiots, some people take the initiative to improve their intelligence. That does not cheapen it, in fact it makes it more respectable than someone who is just "born smart" if there is such a thing.

Intelligence in teenagers is about 60% genetic, increasing steadily to almost 80% as an adult. The reality is we are all trapped by the cruel luck of the genetic lottery, and there is almost nothing we can do about it. "Street smarts" and "book smarts" is just feel good bullshit we tell ourselves whenever we're presented with evidence we aren't as smart as we like to imagine we are.