Despite the pegging mechanism, the price of SBD has been consistently trading at a ~15% discount for the last couple of months. However, there is no way of taking advantage of this (no free lunch), because the feed-based conversion, from SBD to STEEM, takes a week, and the price of STEEM has been consistently losing ~15% per week.
It looks like this is the driving market mechanism right now. Past the pump phase, the conversion function forces down the price of STEEM (at a weekly rate) instead of pushing up the price of SBD. In face of this, there is no incentive for buying SBD*.
This is why I am cashing out.
* Notice that the 10% APR interest has a neutral effect: It is a universal interest rate (invariant to any spending/saving decision), so it cannot magically create value in the (SBD-based) economy. In this sense, it is more like a remurrage: Prices cannot be expected to be SBD-stable, thus removing any apparent saving incentive.