I also need this feature, currently I need to export the image from figma and then use a converter to turn those images into WebP before uploading them to the site.

WebP is supported almost everywhere and a standard when presenting images in the web. This would make the developers work easier and faster too, maybe have the export option only in dev mode..? Or under a setting if it still is too far fetched.

The most important factor is file size and WebP gives you small file size with reasonable resolution.