I would prefer a mode in which, in a pin-code locked state, the extension retained functionality not locked:
- offer to enter a password when logging in to a known site;
- offer to save the password when entering the password manually;
- change the extension icon when you login with a saved password
but ask for a PIN at the time you enter the password!
I understand that this may not work for everyone, as the list of sites where the user has accounts is not blocked, but the passwords remain encrypted.