Cross platform software development is hard. Not all APIs are available or compatible on all platforms and you might end up with 3 implementations for the same feature. With PWA this changed and it's still changing. Offline, cache, installability and push notifications. With Project Fugu more APIs become available to the web platform, like file access, shortcuts, badges to name just a few. APIs that can really close the gap between web and app, that is if the platform allows it... ... If it is allowed cause not all browser vendors are on board.