I wouldn't presume to understand the bananas ideas of Trump and his kindergarten kronies, but I imagine they're looking at an inaccurately large landmass on a mercator projection map and hearing about the oil underneath and seeing dollar signs.
On a map, it looks to be bigger than all of North America, although in reality its only about 1/5th of the size of the US.
(although granted that's still a very large area that they probably see as 'up for grabs' since Denmark is small and far away and the US already have airbases there)
