Only needs a small fix

You are getting feedback about SEO issues likely because when the “delete” option is selected the plugin needs to remove the http_accept line from the .htaccess rules (also the nowebp line makes no sense if the delete option is used).
Since the desktop crawler agents won’t pass the http_accept rule the search crawlers will get 404 errors trying to load deleted originals.
After a few years of WebP conversion experience I’ve found the reason some images come out larger is because they were compressed far too lossy (almost always a small JPG), but there is a command line option for CWebP that will match the original file size so you can do a full conversion to WebP.