Wi-Fi Direct: what it is and how it works
Wi-Fi Direct links two devices over the Wi-Fi radio, with no router. It is not a hotspot and not classic Bluetooth.
Direct answer
Wi-Fi Direct lets two devices build a Wi-Fi link to each other with no access point. Venue internet does not need to exist. The feature only appears if the phone’s Android build offers that API and the permission is granted.
Why it is not the same as Bluetooth
Wi-Fi Direct usually uses a radio with more throughput and, when the hardware helps, more range than classic Bluetooth. It is still a local link. Walls and distance still matter.
In offChat this layer appears when the Android device offers Wi-Fi Direct. Bluetooth remains available for nearby phones even when Direct is missing.