They are authentication and authorization just like a username/password set. I don't see the Supreme Court allowing this if they won't allow compulsion of releasing a password. Right against self incrimination. Should be interesting though.
https://en.wikipedia.org/wiki/Password
There is nothing secret about your biometrics. Especially not while you are in detention.
That would potentially upend decades of case law - the government can compel somebody to produce a physical key (which now includes fingerprints and other biometrics) but cannot compel production of a passcode/combination.
This article talks about a case in the 11th circuit in 2012 and another in the Pennsylvania Supreme Court, Commonwealth v. Davis. Apparently the only time you can compel someone to give their password (which biometrics serve the same purpose) is if the state already knows what's on there. It's called "foregone conclusion exception."
Yet if the government can show that it already knows of the existence and the suspect’s possession of the documents at issue—i.e., that these matters are a “foregone conclusion” and thus that the factual assertions implicit in the act of production add “little or nothing to the sum total of the Government’s information”—then “no Fifth Amendment right is touched because the ‘question is not of testimony but of surrender.’”
You can be forced to submit to fingerprinting, which could also be incriminating.
Here's some interesting copy on similar cases.
https://arstechnica.com/tech-policy/2020/06/indiana-supreme-...