The new Do Not Disturb during Bedtime mode is meant to help you get some rest by dimming the display and hiding all notifications on the lock screen until you wake the next day. You can set it to automatically end based on a time or location, if you so choose.
There were also changes made to notifications that allow you to customize how they're delivered to you. You can instantly manage any notifications delivered to the Notification Center, or have Siri help handle them as well as other things like turning alerts on and off. You can also opt for Grouped Notifications, which lets you view and manage multiple notifications at once.
Screen Time is a helpful productivity tool that lets you figure out how you're spending time during the day so you can identify potentially harmful habits, in terms of apps you use, the notifications you receive, and how often you're picking up your device in general. You can even set up parameters via the App Limits feature to try and help limit how much you're using your trusty phone or tablet. You can even schedule blocks of time that render the device unusable, which is account-based and a great addition to parental control options for kids.
All these new features, including Screen Time, notification changes, and Do Not Disturb will be avaialble via iOS 12 this fall, so if you're interested in trying it out, you can have it all in your hands soon.