What does installing a website as an app(wo/ being web-app)

Honestly whenever I see the +install, I really know there is some optimization that goes on. However, I was wondering whats the benefit of installing a site as an app that does not support it as a web-app? In this case, look at vrv.co, I can install it as a app, but what's the benefit if nothing is stored? What's cached? What's great about it? I really want some explanation because if it isn't better, than why bother with just putting a shortcut instead?