How could this benefit Obama?
1) He thinks they will now pay taxes and it will cure the debt crisis.
2) He will find a way to recognize their employment so that next month report shows "Obama added 300,000 jobs to the economy".
Let’s say someone has been working illegally using a phony S/S number. Now he is given a work permit and a tax ID. The now temporarily legal has to go back to his boss and fess up to the earlier fraud. He’s liable to be fired because he has admitted he is a felon and a fraud. The boss may even have liability for any identity theft.