Now lemme go a bit away from the technical side of things, and switch to potential purposes.
Because that's that bothers me personally - HALE drones are a very rare thing; heavy MALEs are far more popular among 'second tier' military-industrial powers.
1.For Reaper-unni everything is probably quite straightforward - persistent optical(visual, IR) ISR and overwatch.
(1)In peacetime - directly inspect/threaten objects of interest;
(2)In wartime - as per Ukraine experience, low altitude (oblique/side-looking) ISR and spotting for different fires from behind the frontlines&from within the SAM umbrella protection.
NK is...well known for massed fires, and nowadays even for massed precision fires, this drone emerges as a massive potential force multiplier...provided they will be able to defend them.
Curious that they've chosen reaper for the model - i.e. quite a heavy MALE type. Hellfire-hyungs probably were a significant goal.
2. The Global Hawk-ajumma ...
(1)peacetime, given the range and altitude -
1.1. Probably intended to have an in-depth look at ROK, from both inside the DPRK and from international airspace. Altitude here allows not just for more range and better inclination, but, crucially, difficulty to interfere.
As we saw on several occasions recently, MALEs are vulnerable to fighter interference, as they're operating low enough and are completely defenseless from bother (and no, sidewinder isn't an answer). Pissing at a subsonic plane at 65k feet is essentially undoable - that few fighters that can still fly up there are basically unmaneuverable, and can only fly at a significant Mach number.
1.2 Same, but also for seas around DPRK and especially south of Korea. There is a lot of rather scary(for DPRK) activity, and flying ISR presence(Elint, SAR) can do a lot to massively increase DPRK's visibility of the situation around them. Given how far Chinese HALEs operate - that's a jump.
It also allows them to have a visible presence at all those massive ROK/US maneuvers, which is important for events that routinely bring in enough firepower for a decapitating strike. May potentially give DPRK enough situational awareness to start playing long-range anti-shipping threat game.
1.3 Monitoring of potential regional wars, not (yet?) involving DPRK. Reference to the Taiwan conflict. Even more massive fleets and shootings around, carrying decapitating amounts of firepower.
(2)Wartime (Korea) - well, probably ISR (elint,SAR) from the deep? Harder to find survivable enough use, especially since those won't be able to operate just from any airfield.
.3 Of course, since it's DPRK, both are also for export. Cash won't print itself.