User blog comment:Xilinoc/Ch. 591 - Marching Out the ZOMBIES 2/@comment-5496403-20140803003927/@comment-6904925-20140804101337

I think its because that Giselle doesn't give her/his zombies any free will of their own, while Mayuri lets his zombies still maintain their personalities and their will, Giselle just has them go straight in a fight not bothered to even have them dodging, having just go in as mindless drools. (Plus Zombietta was already in bad shape after being hit by those explosions last week).