While it helps LGBT couples in CA and the 10 states that have SSM, it will do nothing for the ones in the rest of the country.
Wouldn't it allow same sex couples who were married in one of those 10 states or a foreign country to be married for federal purposes, regardless of where they live now, even while the state they live in might not recognize their marriage? Not sure what all the consequences of that would be. Though, for example, since immigration is controlled by the federal government, I would think that it would allow the same sex spouse of an American citizen to immigrate as easily as an opposite sex spouse of an American citizen. And this would work regardless of whether the American citizen in question lived in one of those 10 states.