The mission of NIF is and has always been to subvert the test ban treaties. It is written down in the original proposal, which are available on the web from the agency. NIF has no civilian energy applications, and will never have any.
I suppose it depends on how you interpret the intent of the test ban. If the intent was to stop detonations because they are bad in themselves, then it's not subversive. If the intent was to stop detonations in order to curtail further weapons development, then it is.
Detonations are bad in of themselves, they cause various items to become contaminated, causing issues for imaging and science applications. Being able to ignite fusion without using a fission bomb to do it lets you prevent the contamination without sacrificing your negotiating position. Remember, the best lie is the truth, your enemy can't figure out your nuclear weapons don't work if they actually work.
