I have mostly remained silent on the proposal, attempting to listen to what others have had to say who may be better informed. However, the thing I keep coming back is a sentiment that Otto shared on the proposal post.

Yeah, no. If I upload a JPG, then I want it to be a JPG and to stay a JPG.

If this doesn’t have an off switch, then I surely will build one.

I may be among the minority, but when I upload an image to a WordPress site, I have purposely chosen the format. I want my original images and the generated sub-sizes to be in that format. That's my thought-process on a personal level and not necessarily what does the best overall good for the web.

I love what WebP provides and have started using it more and more in recent months on various sites and projects. I even gave it a shot here on the Tavern for a week in early February, at least until one of our readers was unable to view images (older Mac OS).

The great thing is that WordPress has supported the WebP format since 5.8. Folks can already use it, and there is no need to prematurely push the on-by-default proposal.

I don't even necessarily see having WebP conversion as a bad thing for new WordPress installs (should be opt-in for existing sites and definitely an option under Media Settings). However, we need to seriously sit down and address the underlying issue. Namely, that is generated image sizes. And, at this point, I would just be continuing to echo what others have said.