There's negligible advantage in loss going from pl259 to N connectors on HF. You don't have the kind of losses you do on VHF and especially UHF. The only time N is really nice is when you need an intrinsically weatherproof connector -but this is mounted inside the weatherproof box.
If you want slightly better loss specs AND a more convenient, quicker connector, BNC is great. But PL259, as I said, is fine.
It's a (kind of silly) throwback to the radios that armies used in the first half of the 20th century that were large enough to necessitate a dedicated person backpacking them around everywhere. It's still common in ham radio like other traditionalist terms. "Portable station" is more accurate, but maybe boring?