Hmm, i can see it would be useful for copying keys, though how useful a plastic key would be I'm not sure.

It's sort of like the original scanner i had 25 years ago (possibly longer) for my amstrad pcw. You attached a little scanner to the dot matrix head of the printer and it scanned pictures line by line.
This is a slightly updated version of that.

If it could be configured to produce a solid rather than a hollowed out shape, could be quite useful - I assume it's cheap :-)
Anything more than $100 and you can forget it :-)