What's wrong with telling people to go to their website? They apps seems like a thin wrapper around a web app, couldn't they just have people use the web app?

What's wrong with telling people to go to their website? They apps seems like a thin wrapper around a web app, couldn't they just have people use the web app? If you add a link to the home screen, it's almost identical. Not idea, but better than losing 30% of your revenue...