The correct term is now "Purser" on all flights. "First Flight Attendant" is the old term that was used before (especially for narrow-body flights). So someone is probably still just saying the phrase they got used to over many years.

As mentioned, you do need special training to be considered "qualified" to be Purser on int'l and all widebody flights. But even a 737 going from DEN to PDX still has a Purser.