Comment by oktoberpaard

Without having any experience with the APIs to back up my claim, I believe that the WebExtensions API is more powerful in the sense that it allows more complex blocking rules. AdGuard seems to include both options simultaneously, where you have "advanced protection" (WebExtensions API) that only works in Safari and separate blocking lists (old API) that work in both Safari and WebView. This is precisely what keeps me from using uBlock Origin Lite.