Windows 10 allows for a simple PIN input for user authentication. Google thought it might be a good idea to also allow its Chromebooks to do that, just like its Android phones.
Whatever the case, PIN unlock capabilities are now available in the latest developer update under the flag #quick-unlock-pin. According to Chromium evangelist François Beaufort, users will have to reboot, then hit up the Material Design settings to set up a PIN for the lock screen.
Developers are still trying working with Android apps on Chromebooks.