The term "whore" is a hurtful and degrading term. Comfort women in the Imperial Army had a multi-purpose role; they were nurses, entertainers as well. Their role was morale boosting for the men. In that aspect, yes, they are important for the Army and the Soldier.
Many of the Comfort women's roles were not just for purely sexual purposes; many of them (majority of times) were the ones who soldiers talked to to release their emotional tensions, they cared for dying soldiers, provided care and motivation for soldiers before a battle, after a battle.
Your looking and talking from the context of the Chinese aspect, and that's understandable why you think the way you think. But I'm merely showing you the other view, an objective aspect, so to say.
Regards,