Why convert WebP to JPG
Browsers and current apps open WebP, but some upload forms and older programs still refuse it. A JPG of the same picture opens almost everywhere. It is often a little larger than the WebP: Google puts WebP photos at 25 to 34% smaller than JPGs of the same quality.
Transparency and animation
A WebP can be see-through; JPG cannot, so transparent parts take the background color you choose. Animated WebP files are refused here rather than cut to one frame without saying so.
The new files are made in your browser from your images. Nothing is uploaded, and location and camera details (EXIF) are left out.