Chrome OS has always required you to hit the enter key or click the submit button to confirm your PIN code at the login screen. Adding an extra step to the login flow is a security-preserving measure that slows down snooping attackers from guessing your password. Still, some users prefer the convenience of signing in automatically after entering the correct PIN. In the most recent Chrome OS Beta channel update, Chrome OS will now offer to confirm your PIN automatically.
A new toggle will show up in Chrome OS settings that allow you to choose if you want Chrome OS to sign you in automatically after entering the right PIN. Click on the "Security and sign-in" settings and then navigate to the toggle on the page's bottom to find it. The next time you lock your screen or log out, the login screen will have a slightly tweaked interface. Take a look:
Chrome OS automatically submitting my PIN on the lockscreen.
As you can see, Chrome OS conveniently unlocked my screen after I typed in my PIN, but you might've also noticed a new toggle below the keypad to switch between your PIN and password. I personally really like this idea. If I feel that someone might be eavesdropping, I can quickly switch to the password view and start typing my long 16-character password. I wish Google also exposed this toggle when the auto-submit PIN feature is disabled.
The toggle to confirm your PIN automatically will soon roll out to everyone on the Chrome OS Stable channel. This feature may seem trivial, but it is a welcome quality-of-life improvement, especially for heavy users.