Unfortunately in the US, the police can coerce you into unlocking your electronic devices using biometric authentication methods. So I could care less if there is a fingerprint reader on my laptop.
If what you might have on your laptop is incriminating enough, they'll force you to give up your password, or just hold you in jail until you do.
Which may be your preference, and an option you wouldn't have with biometrics. What if you only need to hold out for a month, a week, or just a day?
A police officer on the side of the road can't compel someone to unlock their phone to perform a warrantless search.
That being said, they can't legally do this.