Our current recommend is not to use WebP.
- is not supported by all major browsers
- is generally the same size as JPG
- provides no tangible performance benefits
- does not impact pagespeed score (pointless optimization warning)
- introduces a number of other issues (changes DOM structure, introduces DOM nodes)
- makes no difference when images are lazyloaded (95%+ of recipe images)
We will not be supporting WebP for the foreseeable future, as it provides no tangible benefits and introduces unnecessary complexity.
Why is it being pushed?
It's a format developed by Google that they're pushing as... self promotion is my best guess.
Their initial claims were that it produced smaller images, but this has not panned out in the real world.
It's also being pushed by image optimization plugins because it introduces a new potential revenue stream for them.