When a load switch IC turns off, the auto discharge function discharges the smoothing capacitor quickly via the internal N-channel MOSFET connected between the VOUT and GND pins, thereby facilitating power supply sequencing.
An electronic system consists of multiple ICs and circuits. For the system to work properly, it is necessary to set a power supply sequence, i.e., the order in which to supply power to the constituent ICs and circuits. A relatively large capacitor is connected to the VOUT pin of a load switch IC in order to smooth the output voltage. Unless this smoothing capacitor is discharged properly, it is difficult to set a power supply sequence for a system.
The following links also provide descriptions of auto discharge:
Application note: Basics of Load Switch ICs
FAQ: What is an output discharge function of the load switch IC?