The operator's missing sense of touch
When a person picks something up with their own hands, they instantly feel how hard they are gripping and whether they are about to crush or drop it. An XR teleoperated robot does not automatically give the operator that same sense, since standard VR controllers report position and button presses but not contact force. Without added haptic feedback hardware, an operator can be visually confident a grasp looks correct while having no direct physical feedback about how much force the robot's gripper is actually applying, which is the core overlap this course has with general haptic teleoperation concepts, though the deeper mechanics of force feedback belong to that dedicated subject.
This gap is why force limits are typically built into the robot itself rather than left entirely to the operator's judgment. A robot can be configured to cap how much force its gripper or arm applies regardless of what the operator commands, so that even if the operator misjudges a grasp, the robot's own hardware and software refuse to exceed a safe threshold.