Ironically it's by looking at a globe rather than even a map like this that Greenlands worth becomes more visible. We need to centre the globe on Greenland and see what it tells us.

Greenland has at least two reasons to be worth more then it is now: in the future when the north polar ice sheet melts. The arctic circle becomes a navigable ocean. It's a short way from USA and Europe to Asia (or Russia).

Secondly removing the ice means it's much easier to get the essential hydrocarbons underneath of which there are lots of and which many countries will want.

So the reasons for Greenland is geography, security, control, trade and economy. And by thinking long term. It can also explain some off handed and mocked comments about Canada too.