Nonplussed by samples

Looking at the first image (mountain + river) the jpeg has the sky smooth, but is clearly blocky in higher contrast areas (e.g. bank of the river, mountain-sky interface). The webp is blocky on the sky, and somewhat less blocky on high contrast areas.

I'm not sure this is an improvement. The banding/blockiness over smooth gradient-like areas is very noticeable, and takes up a lot of image real estate. The high contrast edges are improved, but not by a lot...