All you have to do is enable the flag chrome://flags/#quick-unlock-pin, restart Chrome, and go to Chrome Material Design settings page for now to set up your Lock Screen PIN in the new "Screen Lock" section. When it's done, lock your screen with 🔍 + L and enjoy the new unlock experience!
Sure, it's far easier to plug in a PIN instead of whatever you've set as your Chrome OS password, and possibly more secure than using a nearby Android phone for Smart Lock. But you're also not entering the code that will get you into your Google suite — the "keys to the kingdom" as one commenter on Beaufort's post put it. Nifty, huh? Those wanting to dig deeper should check out the source code here.