This is a very strange and unconvincing article. Greenland is massive; and, while it's very hard to give 'worth' to part of a country (and potentially misguided to attempt to do so in most cases), $2bn is pocket change for a wealthy country, and the potential upsides of owning such a vast tract of land are much bigger over time.

If I was offered $2b or such a large swathe of land, I know which I would take.

(The argument becomes crass anyway when you consider that real people live there.)