Now webp support is absent. if you drag’n’drop webp image, it either doesn’t show anything, or make a link that is not visible in preview, and also won’t copy image to attachments folder.
If there is some rules which files are allowed, may be it should be done as option.
Regarding webp is good format. May be it should be converted to jpg/png if it can’t be embedded as is. But lacking it’s support is not so good.