But all it proves is that the document you present has your fingerprints etc on it. Unless they are going to check all passport fingerprints against a data base containing the guys fingerprints,and identifying him/her as somoene else, what real good does this do? All right, once someone has been picked out as suspicious,maybe, but at that point the game is lost anyway.

It'll make it marginally harder to forge passports, but not very much. Any reasonably well organised set of terrorists ought to be able to do it standing on their head.