Independently of that article, I've experimented with webp to find out when I would use it, and concluded approximately the following (of course, somebody else can have different preferences and conclusions):

- If you know how stills from mp4 videos or similar "look like" (when observed so that the compression artifacts are visible) -- that's more-or-less lossy webp. Not something you'd expect to achieve the best picture quality.

- Probably because of its origins, that's also how lossy webp handles scanned or printed images: not good.

I've concluded that I will use webp, but

1) to save the pictures for which I don't care which quality they have, and if I want to use up less bytes: specifically: if I want to save some visual information from some JPEG from somewhere only to store a picture of that not to preserve it in its full quality.

2) when serving the pictures, in scenarios where I want to reduce the amount of data delivered to others, when the artifacts I'm aware of aren't the issue.

Everything else: still no.