Both WebP and Progressive JPEG are commonly used image formats on the web.
WebP has better perceptual quality at a given file size. This means that the compression artifacts tend to be better, resulting in a blur rather than blockiness.
WebP is not universally supported, hence, can only be used on Android, Chrome, and Opera.
Although WebP gives better perceptual quality per byte, it does not support progressive.
Using, Progressive JPEG results in a very fast preview of the image which is very useful if you have a slow or unreliable network. This tends to matter less when using a fast and reliable network.
If your main audience has a fast internet connection, then using WebP is the preferred choice. If your audience has a slow internet connection (e.g. mobile in rural areas), then progressive is a much better choice.