Because without them we wouldn’t have seasons. Happy September equinox, all.
Equinoxes occur when the Sun as viewed from Earth crosses the celestial equator, marking the astronomical change of seasons to longer thus warmer days in one hemisphere and shorter thus colder days in the other. The word equinox means equal night, because around the equinoxes we experience nearly 12 hours of sunlight and 12 hours of darkness.
Saturn only has an equinox every 15 years, because it’s orbital period is so much longer than Earth’s. When Saturn is at equinox, the rings disappear for observers on Earth, because they are directly edge-on to the Sun and thus very nearly edge-on to the Earth. My favourite spacecraft, Cassini, took this photograph of Saturn at equinox back in 2009.