iPhone owners can set up Tap to Wake on their devices to easily glance at the time, or see pending notifications on the lock screen. In sleep mode, the iPhone display goes dark to save battery. Picking up the iPhone and unlocking to catch up on messages and alerts takes time and is likely to kick up your Screen Time totals for the week. With Tap to Wake you can quickly check up on lock screen notifications without opening the home screen.
Siri enjoys delivering answers to iPhone owners whether their devices are locked or unlocked. Sometimes the call "Hey Siri" is even answered no matter who is asking. Pressing the Side button or Home button can also invoke Siri from the Lock Screen. For those who consider this a privacy or security risk, Siri can be completely disabled when the iPhone is locked.
The iPhone X display notch houses critical components used for Face ID, FaceTime and other features. This hasn't stopped people from loving or hating the design feature. Detractors have referred to the "horns" on the iPhone X, which comprise two halves of the status bar. For those who truly can't stand the notch, there is a solution that doesn't involve buying another phone.
Your iPhone has a setting that dictates how long of a period of inactivity it takes for the display to go dark and the phone to enter lock mode, requiring you to unlock it to get back in. It can be annoying if you have something on your screen you are looking at for reference and it goes to sleep on you. Alternatively, if it stays on too long it wastes battery. You can easily change this by heading to Settings -> Display & Brightness -> Auto-Lock. Choose 30 seconds, 1 - 5 minutes or never.
iOS 10 brings quite a few changes to the iPhone's Lock Screen, including raise to wake, rich notifications and widgets among others. Whereas widgets were only available in Notifications in previous iOS versions, they are now available in the Spotlight screen, which is accessible from both your Lock Screen and Home Screen.