Then you harvest life energy or whatever to basically purchase abilities at a vending machine. You could ignore them but you wouldn't be able to purchase the abilities.
So does anyone else notice the similarites here between Big Daddy and the Dragons? You got Dragon Shouts that seem only purchasable by collecting souls of dead dragons.
Anyone else getting that vibe? Are the dragons our new Big Daddy counter part from bioshock? Are we going to see little girls riding these dragons?