The wheel was an extremely important technological development, almost as significant as the ability to control and use fire. Civilizations that made use of the wheel had a greater ability to produce food, manufacture goods, and transport goods and people than those that did not. Because making wheels required metal tools, the wheel added a sort of multiplier effect to the unequal development in various civilizations in different geological areas.
Perhaps the first use of the wheel was for making pottery. The potter's wheel allows faster manufacture of pottery of higher quality. Pottery itself was an important part of early civilization, providing insect- and vermin-proof storage for food, liquids, and other important goods and containers usable for cooking. It was also a medium of artistic expression and useful in trade (one cannot trade wine or olive oil, for example, without secure containers).
Next, water wheels were one of the earliest sources of power other than human muscles. They were a way to put the power of streams flowing down hill to various uses such as creating watermills, used in grinding grain, mining, and other manufacturing processes.
Finally, the wheel was useful as a means of transportation both for civilian and military purposes. Existence of the wheel led to development of road networks and postal and courier services which were economically and militarily advantageous.