Workspace Environment Management (WEM) is a Citrix technology that is specifically designed to optimize the CPU and bandwidth consumption of HDX sessions. It works by intelligently managing and allocating system resources to ensure optimal performance and efficiency of the virtual environments. App Layering is used for managing applications and images, Insight Services is for monitoring, and Provisioning Services is primarily for streaming disk images to virtual and physical machines, none of which directly address optimizing CPU or bandwidth consumption.