That's a good explanation of "how", but unfortunately it leaves out the "why", as in "Why should my users go through the effort of installing a dummy application when they can simply open a URL in their web browser?"
because users prefer to open an app than open a browser. it's like an easy bookmark to your site
but an even easier bookmark could be had from the browser menus.
the embedded site could access Android api's, though.
Easier to make the bookmark vs installing an app, but not easier to use.
Compare # of clicks from the home screen for an app icon vs a bookmark.