A notification that your load is done is actually convenient. It's typically also paired with some sensors that can let you know if you need more detergent or to run a cleaning cycle on the washer.
Mine also lets you set the wash parameters via the app if you want, which is helpful for people who benefit from the accessibility features of the phone. Difficult to adjust the font size or contrast on a washing machine, or hear it's chime if you have hearing problems.