Sega CD cart question

I've come across a country converter cart for a Sega CD/Genesis that's supposed to be good for importing US games to Europe.. now, if I bring this cart over to a US machine, will it do anything productive? If not, is there such a cart to bring imports over to the US Sega CDs?
the datel CDX plays imports, but isn't overly reliable for US systems.. generally a bunch of games don't work, on any of the versions.