The main purpose of a network switch is to connect devices within a local area network (LAN) and facilitate effective communication between them. Operating at the data link layer, it receives data packets and forwards them to the correct destination using MAC addresses. This is essential for improving network efficiency, as it reduces unnecessary traffic and collision domains. By managing data flow intelligently, switches enhance overall network performance, reduce latency, and provide increased bandwidth, making them crucial components in both small and large networking environments.