Answer 1

Progressive web apps is just Google trying to reinvent their apps and create vendor-lockin again by rebranding ordinary HTML5 online web applications that are capable of running directly in your web browser. No DRM necessary.
It seems that their strict application submission policies are forcing developers to bypass the Google AppStore and provide directly to people with HTML5 browser based applications that can run in any web browser, independent of operating system. So no more Android AppStore lock-in.
You can now get the web app directly(sometimes for free) from the developer's website, as these apps run like an ordinary web page right inside your browser.
These HTML5 web applications don't need server connections and can also be used as a stand-alone app.
Check out these HTML5 web apps for free:
Online HTML5 Office Suite:
https://www.ssuiteoffice.com/SSuiteWebOffice.htm
Groot Web Search Engine
https://www.ssuiteoffice.com/search.html
Have fun with these new web apps. There great fun to use and they are also free!!! :)