A number of central and south American countries have followed Mexico's lead in issuing matricula cards; e.g. Argentina, Brazil, Colombia, Ecuador, El Salvador, Guatemala, Honduras, Nicaragua, and Peru.
I've heard regulators for each agency say it would be acceptable as identification, but none of them have put that in writing and I doubt that they ever will. It would cause a political firestorm with a couple of Congressmen.
A person with a cedular card (described by Andy above) who is in the U.S. would be expected to have a passport. A person with a matricula card generally does not have anything else.
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In this world you must be oh so smart or oh so pleasant. Well, for years I was smart. I recommend pleasant.