Why can't Rey Dau Breathe?

I get he doesnt have a breath in the traditonal sense but why cant he shoot his gun? And to add to this, why can't Namielle, the WATER elder swim. Are they(the monsties) stupid?. I still love the game dont get me wrong, ive done nothing but play the game for 10 days straight i think, but when i first got access to them specific i was hyped for those two things specifically cause i wanted Nami to replace my mizu and i just wanted to shoot monsters with the railgun open world😔