One of my particular concerns is the access that the Government may obtain to things that people take steps to secure from other people's gaze. With regard to cell phones, that concern is with fingerprint sensors and FaceID and similar technology.
According to a recent Bloomberg article, the U.S. District Court of Idaho approved a search warrant to compel a suspect to unlock his phone using the thumbprint sensor. The magistrate judge had denied the request, but the Government took the matter to the District Judge who sided with them.
The District Court found that forcing the suspect to apply his thumb to the phone's sensor did not offend the concerns of the Fifth Amendment. The Fifth Amendment protects people from being compelled to give testimony against themselves.
With Georgia having recently re-recognized that its state constitution provides additional protections against the Government compelling a person to do acts that would incriminate the person, how would a Georgia court resolve this question. Would the court see it as the person being compelled to do an act? Or, would the court take the position that no act was required that the officer would hold the person's thumb and the phone together so no action is required by the person.
The bottom line is that if you want your data to have a chance of remaining private, you should avoid biometric locks. Opt for a long alphanumeric passcode instead.