While the hydrophilic property gets the glass wet by spreading water drops on it, water-repellency gathers water drops like a lotus leaf by preventing the glass from dispersing water drops. Even if the glass surface with hydrophilic substances applied has a clear and vivid view when the wiper operates, it gets distorted - as raindrops refract light when they gather on the glass again. Furthermore, an oil film is formed due to many oil substances on roads, making the glass partially wet and appear dirty.
Meanwhile, glass with water-repellent coating doesn’t gather water drops, making it look frosted due to tiny water drops right after the glass is wiped. Even so, raindrops falling afterward do not blur view that much, securing a safe view even when the wiper operates slowly in heavy rain. In addition, it helps keep the glass clean by eliminating an oil film that could be created while driving.