It’s talk, and talk is cheap. Talk is particularly cheap coming from a nation whose government has, more than most governments, exhibited a lack of transparency and trustworthiness (and I’m putting it very mildly here). It’s a promise with no safeguards or independent verification whatsoever.
It is, in other words, basically meaningless as to its literal stated purpose. The only thing it signifies is a willingness to talk, nothing more. Given that we already knew the North Koreans were willing to talk, it’s non-news.
It’s also highly unlikely. Saddam Hussein gave up his nuclear program, and what did it ultimately get him? Overthrown by US military action, that’s what. North Korea (also on George W. Bush’s “axis of evil”) refused to give up its nukes and remains. There is a lesson in that for the North Korean state, and that lesson is not that it pays to denuclearize. This was an entirely foreseeable consequence of going to war against Iraq.