The Articles of Confederation were also important because they set many precedents for the US Constitution.
It called the United States of America, the United States of America. And though it was clearly unbalanced in favor the states it opened the idea of Federalism (the balance of power between the central government and the states). It established itself as the supreme law of the land: an important idea included in the Constitution.
I think it is important also that the Articles allowed the framers of the Constitution some frame of reference for what worked and what didn't. It was a dress rehearsal in some ways. No production can be successful if you don't try it out first. As said in earlier comments, it held the nation together throughout the war and the peace process, then allowed us as a nation to learn how to better establish a lasting and flexible constitution.