[whywhywhywhy]

>All modern image editors support WebP so you'll never notice the difference

This support has always been overstated. Photoshop still doesn’t support it, you encounter other weirdness like Apple Preview.app can view them but not edit them.

[NavinF]

Photoshop definitely supports it: https://helpx.adobe.com/photoshop/kb/support-webp-image-form...

Preview.app is the exception to the rule, but it still has acceptable UX. After you finish drawing the first brush stroke on a WebP file, it will ask you to reopen the edited file as a tiff before you continue editing. No loss of data or functionality