In the US this switch is installed on the open side, or left side for this installation, so people don’t have to reach over the toilet to activate the switch. Also read the placard for the flush switch in the photo above. It says, “Please press the button for at least 5 seconds to flush.” This requirement probably would not be allowed in the US.
Last, look to the right in the first and second photos above for the switch between the toilet and sink. This is the switch for the Emergency Call/Stop feature. See the photo below for a closeup.