Deidara's microbombs can destroy at the cellular level like Rasenshuriken, but every time Katsuyu gets cut, she can multiply. Do you think Katsuyu could just keep multiplying into billions of little slugs, or would she die?
She would die of course. She never showd the ability to multiply that much and it wouldn't matter since size doesn't affect the survival rate of this technique... i think.
She cans separate when she's cut. Her cell reproduce and separate but if the bombs destroy her cells she loses the ability to separate. She clearly dies.