Vantron99

I'm rather new to the game of AOS, but I played a fair amount of older edition 40k. For the new Vindictor models, they have the ability to take a Standard Bearer (Azyrite Signifier) as 1 of every 5 models in a unit. I don't see it as a melee weapon thought and its model doesn't have a spear point or anything, so do they just lose the ability to fight? Forgive me if this is normal for Standard Bearers in AOS, I haven't played against an army that took any in my league yet.