Heh, funny that you found that one. It sure felt strange to buy Noble Brigand against someone who doesn't have anything to steal from, and just signaled (Fool's Gold) he doesn't ever intend to buy anything either.
On this board, I'm convinced the dominant strategy is a Fortress/Rabble thing with schemes, despite there being no +buy. Getting hit by 4+ rabbles every turn is just killing all money-based strategies. At that point I had enough faith in this theory that I was willing to ignore his opening buy and still assume he was also going for the rabble engine.
Because the game will be very long (in #turns, again because of the lack of +buy) a Noble Brigand will actually be quite powerful in the mirror. First you topdeck two green cards, then you donate a copper. In the game we actually played he didn't go for the Rabble engine, and I decided two green cards on top of his deck was more important then an additional copper. But that was the plan.
The fact that Noble Brigand also gives +1$ helps a little bit, but Chancellor would be a lot better for that.