These Apps are only officially available for Chrome OS, so you need a Chromebook to properly run them. If you use Chrome for *******/Mac/Linux, you'll see this message: "This application is **t supported on this computer. Installation has been disabled."
Google developed an Android Runtime for Chrome, so almost any Android app can run in Chrome without manually porting it. Apps are gradually Added to the Chrome Web Store because developers update their Apps to work better in Chrome for desktop. "The app code is all running on top of the Chrome platform, specifically inside of Native Client. In this way the ARC (Android Runtime for Chrome) Apps run in the same environment as other Apps you can download from the Chrome Web Store, even though they are written on top of standard Android APIs," informs Google.