https://www.theverge.com/2017/10/31/16579748/apple-iphone-x-review
Oh look.
"In my early tests, FaceID worked well indoors: sitting at my desk, standing in our video studio, and waiting to get coffee. You have to look at it head-on, though: if it’s sitting on your desk you have to pick up the phone and look at it, which is a little annoying if you’re used to just putting your finger on the TouchID sensor to check a notification.
You also can’t be too casual about it: I had a lot of problems pulling the iPhone X out of my pocket and having it fail to unlock until Apple clarified that FaceID works best at a distance of 25 to 50 centimeters away from your face, or about 10 to 20 inches. That’s closer than I usually hold my phone when I pull it out of my pocket to check something, which means I had to actively think about holding the iPhone X closer"
They also mention you have to pick up the phone to look at it, which is annoying in meetings. Wonder who said that here a while ago.