EvanSchoffstall/OpenEmu — comment on commit 80f3e4baa21f6e06747b84c031c863ae38af7b48
File: OpenEmu/OEBasicSystemResponder.m line 168
By jweinberg:

The reason keyboards are read at the HID level is to allow for modifier keys to be mapped on their own. keyUp isn't sent for pressing the command key for example