FACTA is american legislation that require foreign banks - as long as they conduct business in the U.S. - to report on the holdings and income of all their american customers & accounts to the US. The international reaction has been a huge pain to expats- many banks flat out refuse to serve american citizens (see link below), and it has led to a rash of american expats simply laying down their american citizenship.
From my view (German, Green Card for ~20 years now), there is only minor benefit to becoming a U.S. citizen, and many extremely large downsides; It simply doesn't make sense. The american higher education system is grossly overpriced, and all innovations in that field are globally available via the web and streaming video. The healthcare system is similarly top-loaded, and american salaries are only so high here because basic life services are ridiculously expensive.
Listen: If there's a reasonable chance that they're going to _live_ in the U.S. (which I advise against) then they can make that choice themselves once they're of age. Right now you're going to load your kids with far more problems than benefits if you make this decision for them.