If you have chillblains, you dont need desa?

Thats the impression I'm under. If I'm specced into chillblains, which adds a slow to HB, than putting points in desecration is not needed correct?

This is strictly for pvp, by the way.
Deleted by Redrabbit
Still take Desa its game changing unless your DW then I would go with the sub blood spec which wont allow you to grab desa but you hardly NS as DW anyway
I would keep chillbains and Desecration because you should always be using necrotic strike in PvP regardless if your duelwield or 2h. The chance to absorb some heals is vital for all DKs.
What am I giving up in my current spec to get desecration then?
bump
Probably something like this

http://us.battle.net/wow/en/tool/talent-calculator#dc01!Y!kYehSZeTaQ!Sb
If you don't take desecration you won't really be able to stick to a healer running around a pillar if he doesn't want you to. Not to mention it passively slows their dps as well. Which we all know they're going to be right behind you ripping you a new one.
I will always suggest against taking desecration as with DW frost, since you need to always HB for the RP for KM frost strikes your target will more than likely always be slowed.

I also like going into blood because dks are squishy enough as is and I prefer the survivability from blade barrier and the control from a 1 min strang more than anything to be gained in the unholy tree.