Face ID is, by most accounts, an amazing technology. You pretty much set it and forget it, and the iPhone X just unlocks itself whenever you look at it.
But what if you’re too lazy to point your eyes and your face at your iPhone whenever you want to look at it? What if you prefer to give it a sidelong glance, to show it who’s boss? Then you can disable attention awareness, which speeds up the Face ID process and unlocks your iPhone X faster.