The FBI has already made it quite clear that they're trying to use these accusations as evidence that the US needs to be afraid of cyber attacks.

I've seen a lot of people wonder this, but they flat out state in in an official statement on their website:

"Further, North Korea’s attack on SPE reaffirms that cyber threats pose one of the gravest national security dangers to the United States."

http://www.fbi.gov/news/pressrel/press-releases/update-on-so...

Second to last paragraph, second sentence.