You'd only ship the library to polyfill for legacy browsers that don't support the format and don't have more efficient native decoders. This is an alternative

You'd only ship the library to polyfill for legacy browsers that don't support the format and don't have more efficient native decoders. This is an alternative to having an image pipeline where you encode your images in multiple format or if you have sufficient images to make up the 56kb initial download and are willing to comprise on the initial load. It's also a good way to start deploying the technologies before it receives full adoption.