This is interesting for the *second* reason given.
I love WebP. For browsers that can render the images, it's a huge savings. But since not all browsers can, you have to have JPEGs as a backup. This was the first objection: default WebP doubles the disk storage requirements for WordPress images. Since some sites generate a dozen sizes for each upload, that would mean generating 24 derivative images for each uploaded image. I think a plain WP install ends up with at least four copies (original plus three derivatives), so even there you would end up with seven copies.
The other reason was Google's involvement in pushing the WebP initiative in WordPress
“There are also significant conflicts of interest,” WordPress agency owner Andrew Wilder said. “WebP is a format that Google Created — and it’s Google Engineers who are leading the Performance Team. WordPress agency owner Andrew Wilder said. “This proposal is designed to serve Google’s interests (making it easier and cheaper for them to crawl the web). And the increased cost for all the additional storage space needed will be borne by site owners, not by Google.”
https://wptavern.com/wordpress-performance-team-puts-controversial-webp-by-default-proposal-on-hold-after-critical-feedback
