Why is there a need to know computer networks?

it makes you a stronger candidate for different jobs such as network engineers, network technicians, network administrators, system's administrators etc

Importance of Computer Network : Computer Network is an interconnection between computers or we can say computer network is group of computers linked to each other which enables one computer to communicate with another computer. It acts as basis of communication in Information Technology (IT). It is system of connected computing devices and shares information and resources between them. The devices in network are connected by communication links (wired/wireless) and share data by Data Communication System.