Google’s John Mueller said on Twitter there is maybe a small bandwidth savings when it comes to GoogleBot crawling your site when you use webp over jpeg image formats. But then you would only see that difference when the site is a “very image-heavy site.” So normal sites probably wouldn’t really see any bandwidth savings there.
Here was the question:
Kevin Indig and John Mueller responded similarly:
John Mueller of Google added that you “shouldn’t see any difference with regards to user-facing SEO.”
Forum discussion at Twitter.