ChromeOS is essentially the Chrome browser with a bit of window-dressing. There’s a desktop space that lets you choose your own wallpaper. There’s a start button in the lower-left corner for launching apps. There’s an app launcher shelf where you can pin your favorite apps. There’s a tray in the lower-right corner that provides quick access to Wi-Fi, Bluetooth, volume and settings.
Despite these various accoutrements, nearly everything you do in ChromeOS is done inside the Chrome browser. When you launch an app, the default action is for it to open as a new tab in Chrome. If you are like me, then you have enough tabs open in Chrome at any given moment without your apps adding to that figure. Thankfully, ChromeOS has an easy setting to change this behavior.