Yea I feel like this article is pretty misleading. It would be better if Google officially supported removing the entire ChromeOS and doing a full install of any Linux distro you want. This isn't really running Linux on your Chromebook. It's running a chroot of another distro under their Linux kernel/GUI layer. It's pretty different.
It's not even a chroot. That's how crouton works.
Crostini, the google provided solution, actually runs all the "containers" under a KVM virtual machine. So it's even more abstracted.
