Question about Philips Hue Wandschalter Modul

No and yes. The WSM is only connected to the physical switch. If this is activated, the WSM sends a zigbee command to the bridge. This then switches whatever is programmed. The motion detector does the same. The cables that were previously on the switch are bridged with a WAGO 221. The load is therefore always on. Of course, you can use the WSM in parallel with the motion detector and control the same device. But you cannot control the WSM. Here you need a Shelly 1 or 1PM (possibly Mini) and homeassistant.