Any Chromebooks has the capability to use Crouton and what Crouton does is allow the user to use a chroot environment to run Linux from withing ChromeOS. Once Crouton and an Ubuntu are installed the user can alt+tab from ChromeOS to Ubuntu at any time.
Ranked in these QuestionsQuestion Ranking
Pro No need to be online always.
There is no need to be connected to the Internet all the time to work. Although chrome machines usually are not so powerful and they can't be used for tasks needing high computing (such as code compilation, data processing) but Crouton at least allows to work (like coding, version controlling local copies with git) completely offline.
Pro Easily switch between ChromeOS and Ubuntu
Crouton allows for the use to alt+tab back and forth from ChromeOS to Ubuntu seamlessly. No rebooting the device, no logging out.