That argument works for fingerprints because it’s possible to replicate them (kind of) but how do you replicate someone’s eyeballs assuming supervised setup ?

If we assume "supervised setup", then doesn't that negate the fingerprint issue too because a supervisor can tug off fake-fingers and wash tips with alcohol etc?

Either way, I think this is one of those "if it was used properly, people won't like the limitations, so they'll use it improperly" situations. Kind of like with social security numbers.