Why are Flaggllents Really good?

like Ik this sounds weid but i think in terms of The empires T2 Infantry They're better than spearmen and pretty much only worse than Greatswords If you arent playing as volkmar but even than They're still more useful

and it makes greatswords redundent as the COS since you want to be building as many shrines to sigmar asap and they're cheaper and have unbreakable like i seriosuly dont understand how Good Flaggents are when they're Fking smelly Religious Fanatics

Ig sigmar is really with them