What is this button ??? Prius 2024 LE

The wipers aren't heated though. The button just turns on a heating element by the wipers. You don't want the wipers to come on while they are still frozen to the glass.

I see that some other Toyota models include a wiper with the rest of the elements. I'm from the few examples, they are North American models. Despite being sold here, the Prius is a Japan model, and the button difference has to do with the reason why early Prii for the US didn't get the EV button.

The KISS solution used by others, like Ford and Subaru, is to just have the wiper de-icer come on with the rear and mirror defrosters