Interesting, my site is hosted with siteground, I am not aware of the ability to use webp images, will have to look into that, although I suspect I would need to configure the site some how to use the webp images, and not just upload webp copys.
There is an option to do that. You don't have to do anything, it converts the images to WebP. I know that some of the older customers are still stuck with the Cpanel dashboard, which doesn't have this automatic option. Speak to siteground to get it updated to their own new control panel.