The "key piece" is support for "desktop web apps".

The article explains what it is, and champions it (perhaps to get the click friendly title, perhaps legitimately). But I have never felt the need to "run" a website in a separate "app".

If you use these, and can see their use case, please help me understand. Is the point that the web browser opens a new window and hides its toolbar to give you more screen real estate? Changes icon to match the favicon, so it is easier to switch to that window later?

What usability features am I missing out on if I just go to the website in my regular browser window, like the caveperson I suppose I am? :)