I've ran a couple in the sideboard for various reasons. Tabernacle is fragile (it even dies to itself) and you would have to cut lock pieces for it. I don't think you can cut prison, and I do think a 2/6 is better than something uncounterable.

In certain situations it could be good to side a couple of them into the deck. But I don't think you can run even narrower control cards than what the deck already plays.