Why was a good education important to ancient Egypt?

A good formal education was indeed very important in ancient Egypt. It should be noted that boys were much more likely to receive an education than girls as there were few careers available for women. The importance of a good education was made clear by the many different jobs available to ancient Egyptians. Many of these jobs, such as builders, architects, scribes, and engineers, required a large amount of education (usually provided through apprenticeships). Egyptians felt it necessary to have many well-trained workers in order to keep their society functioning on a high level.
Furthermore, a good education was very important to ancient Egyptians because their agricultural cycle relied on several complicated concepts. Ancient Egyptians planted and harvested their crops based on the flood cycles of the Nile River. In order to help predict these seasonal floods, they needed astronomers to keep track of the passage of time, engineers to build irrigation systems and waterworks, and scribes to keep detailed records. Additionally, the logistics of organizing laborers and farmers, and deciding how much grain to store for possible lean times ahead all required a significant amount of knowledge and skill that could only come through a good education.
In short, without the availability of a good education, the ancient Egyptians would have had a much more difficult time growing their grain in the unique environment of the Nile River Delta and delivering it to a large populace.