I don't think we should care about BTC. Let's separate them. Rather, connection between bitUSD and fiat should be paid attention.
I disagree. Once gateways are setup, Bitcoiners will open the client and see BTC IOUs available just like the ones that they are familiar with, but that they currently think of as "deposits". Along side those IOUs they will see the option to trade those IOUs for BitBTC. Once they see these two options conveniently available in the same trading interface, they will start to make comparisons between the two, and this will be the catalyst for the masses to figure out: "Yeah actually I think 300% collateral tied up on a blockchain is better than an IOU with counterparty risk. These BitBTC are even better than the real thing."
Thats how I envision our mass adoption happening.