Full feather once to show the students what it looks like. Takes forever to get the engine back up to temperature.
Some schools do a landing with a shutdown engine to show the reverse yaw.(live engine creates more drag than a feathered engine when throttles are at idle)
Feathering the engine every time sounds like a hard life for the engine and an accident waiting to happen. Sure he didn't mean that he mixture cuts rather then simulating with throttle as some schools do?