North Korea ,made a blunder I think. By being petty and attacking a company it doesn’t like, it reveals its cyber capabilities to the world giving a notion to enemy governments as to how to harden and protect their own computer networks. It would’ve been better for them to have kept their powder dry over this one movie!
No one has yet to readily prove the NK behind this. Some hints have been given of a insider helping.
But by doing this North Korea gained a bit of respect, on an issue the US can’t declare war about. But you’re correct, they could used their knowledge to do a lot of damage to hostile governments.