Does the Wyze Sense require a Wyze Cam or can it be simply powered with a USB cable?
WYZE Sense requires that a bridge be plugged into the back of the camera, so short answer is yes a cam is required.
As @WyzeJasonJ says the Bridge module integrates with the software in a Wyze camera so the camera is required.
The Wyze Sense Bridge uses the WiFi capability in the camera to communicate its events. The bridge is not designed to function when connected to any other host.