Configuring a Voice VLAN is crucial as it allows VoIP traffic to be separated and given higher priority on the network, ensuring better quality of service and reduced latency or interference from other network traffic. This segregation helps in effective traffic management and enhances the performance of voice communications. 802.1Q tagging is for VLAN identification on frames but does not specifically prioritize voice traffic. Speed and duplex settings optimize the performance of an interface but are not concerned with traffic segregation or prioritization. Link aggregation, meanwhile, increases bandwidth by bundling multiple links, but does not handle traffic type prioritization.