aren't white zetsus really weak? why does kaguya need an army of them

[ShinjuMadara]

Spiral Zetsu alone was Kage level, Imagine what Gaara Zetsu would be like.

 

[Zol]

We don't know what she needs them for, but these Zetsu may be stronger than Madara's/Obito's since they are formed through the Shinju from actual people, while Madara used DNA on the Gedo Mazo.

 

[ultraChalk]

Probably trying to beat quality with quantity.