The reason most of these islands are of such importance is because territorial waters, customs zones, and exclusive economic zones are extended by any sovereign land permanently above water, according to the United Nations Convention on the Law of the Sea that binds almost all states.<p>So these little islands determine which state is legally entitled to write legislation that determines taxation, shipping, airline routes, oil, fish, and any other territorial, customs, and economic rights in the area around these islands.<p>See e.g. <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Territorial_waters" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Territorial_waters</a>