Oda did jack dirty on screen, but i definitely see why hes worth 1bill.
He's just as reckless and hard to put down as whole cake luffy. For all non admiral marines and run of the mill kingdom militia, jack would be a fucking menace. He had a ship full of fodder and still challenged fujitora, tsuru, and sengoku. 1 ship vs 3 and he sunk 2, and the fucker didnt die.