You no longer can say that it's hard to emigrate to the USA: you just need to enlist, give up your freedom and possibly your morals! Grrreat deal.
Obviously there are paths to citizenship. But some kinds of temporary visas don't offer a path to citizenship (like intercompany transfer L visas or F student visas) and this program could be useful to people on those visas if they'd like to stay.
[1] http://www.voanews.com/content/us-issues-million-green-cards...
The languages of other many US allies are on the list as well.
So, this program is at least not entirely a Bay of Pigs style plot