I think BitUSD will end up being fairly stable in the long run. What will be interesting is seeing how assets like BitGold react, since it should be a speculation on gold, which is already a heavily speculative commodity
The big difference is you can have asset classes which are technically impossible to have in the physical world. Forget BitGold, think bigger.
BitUSD will provide the stability necessary but what stops you from combining BitUSD, BitGold, and something else to make the perfectly stable currency?
Or you can create a currency which is perfectly stable but which gives 10% returns for years straight, or 20%, or 40%. There really aren't a lot of rules here and we don't know what can be created.
I think if BitUSD starts out cheaper than a dollar why not buy as much of it as your dollars can afford because it wont be cheaper than the dollar forever. If at any time in it's lifespan it is more expensive than the dollar then you will make extreme profit with minimal risk. I think it would be a better play than Bitcoin even because it's almost a sure thing that it will be a winner. Statistically it would be similar to 50% chance that you'll get your money back soon and the chance rises the longer you have your money in that form until it reaches almost 100%.
Of course that all depends on the system working as intended and the dollar staying as it is now.