The dummy display enables “clamshell mode,” which lets your MacBook stay awake even with the lid closed, provided that it’s also on AC power. If the MacBook is not connected to power, the clamshell mode isn’t activated and it will sleep normally.

Adrafinil simply disables the global sleep without spoofing hardware, and re-enables it once the agent is done working, the temperature is too high, or the battery is low.