WLAN controllers help simplify and reduce the costs of deploying and managing wireless networks. They work with Cisco access points and management software to provide scalable and reliable wireless services for applications like voice, data, and location tracking across enterprise environments like branch offices and outdoor campuses. Key benefits of wireless networks include flexibility, faster response to business needs through centralized management, quality of service for voice and video, and network-wide security policies. Cisco wireless solutions also offer features like dynamic channel assignment, interference detection and avoidance, load balancing, and coverage hole detection to optimize network performance.