The difference between full-device encryption (Marshmallow and prior) and file-based encryption (Nougat and above). It addresses many of the shortcomings of FDE, allowing for far more convenient decryption.
“When you power on an FBE-configured device, it starts up in a secured Direct Boot mode with access to only the DE storage (the utility closet). Direct Boot allows many of Android’s core processes to start up, enables apps to handle critical notifications or to provide important accessibility services, and displays a secure lock screen with the prompt to “Unlock for all features and data.” Developers can register components of their apps to be able to run during Direct Boot and access DE storage. In this way, you can continue to be notified of alarms, calls, or SMS messages even before unlocking the device. Note that the functionality is intentionally limited for your privacy and security — incoming calls will display the phone number but no contact details, and you’ll receive a notification that SMS messages have been received but will not see any information about those messages until you unlock the device.”