I was not targeted for this offer, but called Citi to find out if I would be eligible. CSR said, Yes, if I had both a Citi AAdvantage Credit Card and an Aadvantage Mileage Account. According to her, having both made me eligible to get the bonus miles.
She also said, as others here have noted, that the Checking account (either Regular or CitiGold) could be downgraded to Basic Checking after two months, provided I’ve satisfied their “qualified transactions” requirements (direct deposits, online bill pay, debit card transactions, etc.).
If this thread is still open in a few months, I’ll report back as to whether or not I got the miles and how much effort it took to see that they were posted to my account.