8 GPIOs on the I²C bus — what the 25 mA sink buys you
The I²C interface runs at 100 kHz standard mode, and the part includes a POR (power-on reset) feature that holds the outputs in a known state until the bus is configured.
Interrupt output — saves you from polling the bus
An interrupt output pin (INT) is present, which asserts when any input changes state. That lets the host MCU stay in a low-power sleep mode and only wake when a button is pressed or a sensor trips, rather than polling the I²C bus every few milliseconds. On a battery-powered panel or a remote sensor node, that interrupt line can cut firmware complexity and average current draw noticeably.