Good question as to what came first. here is one theory
The final end of any land promontory projecting into a body of water tends to be called a "point" .Thus ships/boats would refer to "rounding the point" in order to cross from one shore bay to another. Similarly when swinging the basketball ball from one side of the 1/2 court to the other, the ball is seen to change sides once it passes "over the top" of the keyway circle and is passed down/out to the other side.
So it would be seen as fairly natural to call the location on the court that was about 1/2 metre further out from the centre top of the keyway as "the point" .
So then giving that "point" name to the player who tends to go there would seem logical. As they are then the player that becomes the intermediary passer / receiver to swing the ball from one side of the court to the other by the offence, between the 2 wing or "45" players.
but - hey who really knows ?