But if it dosen't suck too much then it is useless because that is the reason why kisame uses samehada to absorb a significant amount of chakra from the opponent.That is if Samehada consumes too much of the natural energy, than the shark sword would turn into stone.
Similar to what happen to Gakidō (Preta Path) of the Six Path of Pains. Naurto, when in Sade Mode, resisted Gakidō's absorption hold by collecting the natural energy which caused Gakidō to turn into stone because it was too much to control. Natural energy is unlike regular chakra.But if it dosen't suck too much then it is useless because that is the reason why kisame uses samehada to absorb a significant amount of chakra from the opponent.