Whats the point of the Nighthaunt procession battalion?

[KHHaunts]

I really be missing something. But i keep reading it and cant say the difference.

The procession battalion gives you the exact same ability to stop wounds and mortal wounds on a 6 as the armies battle trait (and replaces it)

The effect is the same the rollnis the same and the range is the same.

So why would you pay 80 point fir an ability your army already has?

Have i missed something ornis this an error?

[Ove]

Its within and not wholy within

[JackStreicher]

Because it stacks (just a guess I don‘t have the Battletome yet)

[Sception]

It explicitly does not stack.  It is "within" rather than "wholly within", but that's not exactly a compelling benefit for such a huge formation.  It's too big to use in reasonably sized games anyway though, so... *shrug*.

[themortalgod]

I suppose it makes the ability a little better, its kinda a horrible bonus, but lets be realistic. That thing requires 7 warscroll battalions. Almost no one is ever going to use that one anyway. Who cares if it sucks. 

[KoalaSnok]

Its so large it can only be used in apocalypse size games. At that size, it would take hours upon hours of measuring to make sure units are wholly within 12". Its probably there to make these games less of a headache for the few people who ever play at that size. 

[Sception]

While it doesn't stack with the deathly spirits battle trait, it does stack with the frenzied fervour ability of the shroudguard battalion.  It's a shame then that the shroudguard is the only nighthaunt battalion that you can't take multiples of in a procession.