So this would have no effect, because you can simply embed Chromium in your app instead of using the system-provided WebView. Because Android is very fragmented

So this would have no effect, because you can simply embed Chromium in your app instead of using the system-provided WebView. Because Android is very fragmented and there are still a significant amount of devices out there running less than Android M when the web view was made an upgradeable package, there is, at least for now, a very legitimate reason to ship your own browser implementation within an app that is primarily implemented using web tech: The Web View implementation shipped with M and earlier is not sufficient to run such an application.