The thickness of a passport is only a few millimeters, but what it carries is a country's credibility built up over decades or even centuries. The more visa-free countries there are, the not necessarily more free the passport is, but the more people around the world are willing to trust it. This trust comes from national credit, citizen credit, diplomatic credit, economic credit, and institutional credit. The value of a passport does not lie in how many countries it can take you to, but in how many countries are willing to believe where you come from.