Yeah, it wouldn't work for all social defenses, but it might work in the sense of letting you see someone's reactions to, for example, you calling his bluff safely.
I would say knowing what you're opponent is going to say is always be a benefit to social combat. In repartee it should be obvious how it works, you can get some extra seconds to think of a comeback, or you can beat them to the punch and make their biting comment look less biting.
For something like intimidate, if you know the tact their planning on taking, you can remain in control. You know what's coming so you can prepare for it. It will still suck, but you know how and why it will suck, so you can steel yourself for it. Furthermore you can use that knowledge to turn it around on them. They start to detail exactly what they're going to do, and you finish what they are saying word for word, and tell them to get on with it. That might rob them of their conviction.
And maybe it won't. That's why you still roll. Maybe knowing what happened and planning for it wasn't enough to prevent the big scary guy from being that damn scary. And maybe it was. The dice will tell you.