I remember seeing one of these back in the day sometime around when the Multi Game Hunter came out. Cool for a history piece if you're into backup units, pretty pointless nowadays with the Turbo Everdrive.
I agree with you wholeheartedly, if one were to only planning to use this to play games.
However, it was also used to extract the contents of cards - rare prototype cards are still among those which aren't circulated. Of course, ensuring that the transfer to diskette is clean, and then transferring that to a modern PC, may be more of a pain than most people are willing to put up with.
As I recall, there was also a mode where it would download from a computer - but that may never have actually worked (as I never saw it work), and standard computer interfaces have changed considerably since then, so it's probably not worth playing around with.
These copiers were all made in either Hong Kong or Taiwan (or designed in Hong Kong and built in Taiwan, for plausible deniability), and generally sold to the West through Hong Kong intermediaries.