That's the origin of the EU, building a shared market for coal and steel. I'm not going to try to convince the Marxists here, but those economical ties did provide shared prosperity, stability, peace and friendships over the decades. Now, I don't know if it would work out for the specifities of Iceland. They are probably already benefiting a lot from the EU without needing to participate more actively. https://en.wikipedia.org/wiki/European_Coal_and_Steel_Community