Handcuffs are designed so that one officer can put them on and another can take them off. If that weren't the case this situation of being able to print 1 key for all handcuffs wouldn't exist - they would simply make unique keys per handcuff.
However, in a broader view, yeah, there are probably better ways than fingerprints handle keys once electronic locking mechanisms are introduced. Probably something akin to a 2-factor cryptographic mechanism.
I feel though that my larger point is getting lost in this thread. It was/is:
Just because a security technology doesn't work for reason $x in situation $y, that doesn't mean that the weaknesses also apply to situation $z.