Clearly for sheet/thin materials.
My guess is a specialist production system as has been said to reduce toolchanging.
At that price I expect there was an oversupply or more left at the end of the job when expected and chronos snapped them up cheap.
Probably worth having for hand tapping things like garden gateposts or roof trusses when you don't want to risk your best set. For about £4 keep it in your toolbox for emergencies.
Neil