What you lose:
- 50% curse resistance
What you gain:
- +10 to attributes (in your context, a doubled pool of AP) and +1 to the learn rate of both companions
- Leadership on the Knight, which, among other things, will speed up "gearing" the squad with injury protection (it will boost the Kanamia doctor)
- A couple of free skills (I assume heavy armor and one of the special attacks) on the Knight