Originally Posted by Imora DalSyn
I could see hearing someone behind you, but sight cones are fine. You don't have eyeson the back of your head.


Agreed, but at the same time you don't need 6 seconds (a D&D turn length) to look behind you when you hear something. Its part of the simplification/stylization for ease of use, like your reach with an average sword wouldn't be just 5 feet.