That's one mother of a plane. With 7800 kg MTOW it's in class of the WZ-7 Soaring Dragon (or was it WZ-9?), weight wise. With 12 km ceiling it probably trails behind WZ-7 in altitude.
I guess there still might be some merit for PLA to operate both types though, if CH-6 is cheap enough. Not sure about its strike capability against peer opponents, though. Still, I'd say it may have bigger chances of finding most of its market as an export product.
Of course it is going to have much less loiter time when laden with weapons. 2 tons of weapons is A LOT.
Its two small diameter jet engines are not really an optimal way to achieve great endurance anyway. It looks to me that was just the manufacturer working with what they had.
Certainly, comparing this drone with some smaller drones that cruise at 200 km/h or so for 20+ hours with a few hellfire missiles isn't really fair.