What is the importance of cuneiform to the development of Mesopotamian civilization?

Cuneiform is the method of writing developed in the valleys of the Tigris and Euphrates Rivers, the area that became known as Mesopotamia. It had the advantages of any form of written language. It enabled people to keep accurate records. It enabled government decrees to be published so that law was fixed and reliable, not dependent on any one individual's memory or judgement. It enabled many types of knowledge, such as observations of the stars and planets, histories, and artistic productions to be preserved and passed to peoples in distant areas or future generations. Although there have been some civilizations without a form or writing (the Inca were one) the use of writing makes organizing government, work projects, war, and trade much more efficient.
Cuneiform did have some disadvantages. Since it was not an alphabetic system, there were a large number of signs—1500 at one point. Such a complex system obviously required a long period of study to master. For this reason, literacy was limited to priests or trained government officials. A common farmer, craftsman, or merchant could not afford the time to learn to read and write.
The use of cuneiform began around 3000 BCE and lasted until the first millennium CE. It was adapted to the needs of several different languages and cultures, including Sumerian, Hittite, Assyrian, and Babylonian. Without some form of writing, it is unlikely that anyone of the city-states in these valleys would have become well organized enough to grow into an empire. Cuneiform was eventually replaced by alphabetic systems.
https://www.ancient.eu/cuneiform/

https://www.britannica.com/topic/cuneiform