There's a chrome extension by Google that provides a supported way to ssh on ChromeOS, from the device. There's limited support for SSH keys built in, and there's also a mosh extension.

https://chrome.google.com/webstore/detail/secure-shell/pnhec...

(It's pretty easy to enable developer mode in order to allow unsigned code to run, and then Ubuntu/other Linux can run it in a chroot, though education/corporate deployments can/should prohibit that by policy, so isn't relevant to the larger discussion, though it means personal ChromeOS laptops can be quite functional.)