What this USB power switch does on your board
The BD6516F-E2: The switch is controlled by a non-inverting On/Off interface and does not require a separate Vcc supply — the gate drive is derived from the load voltage itself, simplifying the enable logic.
Protection set and status flag
Built-in fault protection covers current limiting (fixed threshold), over-temperature shutdown, reverse-current blocking, and undervoltage lockout (UVLO) — the sort of comprehensive guard band that keeps a USB port from collapsing the entire 5 V rail when a shorted cable is plugged in. A Status Flag output (open-drain, active low) signals over-current or thermal fault conditions, so a host controller or supervisor can log the event or retry the port.