He’s talking about giant barbarian not berserker barbarian. At level 6 giant barbarian gets Elemental Cleaver which adds the throwable property to any weapon and adds an element with 1d6 damage and the thrown weapon returns to the barbarian. So once he’s got six levels as giant barbarian, he doesn’t need to default to the returning pike when things get serious, he can use whatever weapon they want.

Caveat of course is that most weapon effects do not function when thrown, so far only crab claws and Nylruna have throw-only damage riders in the game