Originally Posted by
HIDDY
It is an option as Argentine immigration aren't concerned which passport you choose to enter with as long as it's valid and affords you the right to enter without a visa or having to pay the fee.
US airline staff on the other hand can get a bit confused when it comes to dealing with people travelling on non US passports.
This would get confusing. My US passport (and my tickets) are under my married name. My EU passport is under my maiden name, since Spain gave me a hard time about changing my name when I married.

I can't even begin to imagine trying to explain all of this to US airline staff.