Imagine someone trying to become PK without a D. You see no difference?
I mean Big mom herself also says if she had the giants she'd be pirate king and even fuckin Doflamingo a Celestial Dragon said if he had Law's devil fruit he'd get the National treasure of Mariejois and he would become pirate king somehow... I mean we know it's Luffy who will be the one but there's been a good number of other people who have come up