Quote Originally Posted by cwolff View Post
I speculated that it's a self incrimination thing. If they get hung up on charges outside of this proceeding their lawyers can say that they weren't under oath and not to use the transcript. They'd risk running afoul of laws relating to lying to congress but it'd be the best case out of a bad situation.
Yes, that's also a big part of it.

The whole thing was also a deal struck to get Manafort and Trump Jr to turn over extra documents- which is insane. Congress has subpeona power. They don't need to "cut deals" to get the documents they need for an investigation.