What is SVG?
SVG is a drawing rather than a grid of pixels: shapes, paths and text described in XML, so it stays sharp at any size. That makes it right for logos and icons and useless for photographs. Converting it to a raster format fixes the size it will ever be.
What is WEBP?
WebP is Google's image format for the web, and the rare one that does both jobs: lossy compression that beats JPEG at the same quality, lossless compression that beats PNG, and an alpha channel either way. Every current browser reads it; older software often still does not.