I can't see any upside to that for Kim. Right now it's not like he has to worry about his favorability polling. His regime depends on his army. The only way to p-ss off his army would be to interrupt their standard of living, and provoking US strategic bombing of DPRK military facilities would downgrade a lot of officers' quality of life to quality of death.
NK hasn't done anything they haven't done a thousand times since 1955. This is the language and the BS they do. The smallfry always talk tough at the bar when the gunslinger is in town. This is nothing different. While it's possible their actual capabilities have changed, (1) that doesn't matter since the only way they stay alive is by never, ever using it, and (2) I would tend to doubt it anyway. This whole thing smells to me as a way of squeezing another few trillion out of the taxpayer absent any actual threat to US security. This looks like a lobbying effort between the DOD, the contractors, and their enablers in government (both sides of the aisle) and media (likewise). It's a hostage crisis, but the North Koreans aren't holding Americans hostage, the folks who directly benefit from these expenditures are holding the taxpayers hostage. (3) Obviously, Trump gains from a wag the dog scenario. He's at 30-something approval; in case of a war his approval would go to 80% overnight -- most of the voters are lower order primates who respond to fear with aggression and a deep psychological drive for a Strongman.
So no, I don't thing Kim wants to mess with any of that.