It has been proven to be more effective to imprison Powerful daemons rather than "kill" then as they are only eventually reborn in the warp. While these imprisoned daemons can eventually escape, it does weaken the strength of future chaos attacks. Ergo I theorize that it takes less energy to summon daemons than it does for them to free themselves from imprisonment. It only requires maintenance and not building damn hive cities around their prisons.... sigh, humies.
So maybe the remaining Death Star Blackstone Fortress, can do something useful before it's destroyed.
What happens when we reach 20,000 pages? Do we kick off the great crusade to unite the lost threads of forumanity and bring them into the Imperium of STIWTHR?