If not, they're less than meaningless. I think China got 3 shiny new islands and the US gets to waste fuel by sailing by them and watching China land fighters and dock ships at her lovely new facilities.
On a side note, it was the Viets who started land reclamation first. A couple of years before China. Of course reclaiming land isn't like making pho and those viet monkies now realize what a hornets nest they've stirred up once Chinese industry started playing their game.
