Clamshell keeps your Mac awake and the work running while the screen goes dark. Open the lid, it wakes clean.
Close the lid.
No need to stay plugged in. It survives power transitions without dropping the session.
The built-in display sleeps. Saves power, and hides your work when you walk into a room.
A clean wake every time. No relaunch, no hang, no black-screen guessing game.