High speed neutral coasting

[kk2002s]

I remember reading not to long ago that Engine braking generates a much higher vacuum within the engine which places an unusually high demand on the AOS
It does place strain on the Clutch and drive-train, basically opposite of acceleration or steady driving

Also with the thought behind the smaller under drive pulley reducing RPMs on accessory items, idling certainly does that

This is something I think about when I take long trips into mountainous area where I'm driving 4- 8 hours at a time and any releaf I can give to the car is a plus