He did agree that he would offer recompense, so rezzing him is likely to be worth it just to get that reward, and he's amenable to working with us, and seem mainly interested in knowledge, so it's likely he will be ready to help with research, in return for getting to see all the interesting research objects we have.
I don't want the main party to grind for loot and undead, I want the Draco-lich and a few others to grind for loot and undeads, and it can't be left for later, the Draco-lich don't plan to stay a lich long, so if we want to use his ability to command undeads to gather sacrifices, we have to do it now.