It also offers transparency just like a PNG. So in an age where pagespeed is of grave importance WebP images could make a massive difference in your conversion rate.
WebP is supported by Google Chrome and Opera there is also a Photoshop Addon for all you creative cloud users so you can get to creating your new images straight away.
The maximum dimensions of a WebP image is 16383x16383 pixels.
2017 is all about page speed. So making the switch to WebP might be the ace up your sleeve your competitors aren't using.