You can also use a privacy screen protector. Or use the two factor fingerprint unlock, which requires both a fingerprint and a PIN to unlock. And that's only after first unlock, so you can still use a separate, strong passphrase for BFU state.
Sure, a privacy screen makes things a bit more difficult for surveillance, because the camera would need a line of sight at a low angle, but once the code is known, the attacker can force a fingerprint and input the code.