I was listening to @lukestokes talk, few weeks ago. He mentioned that even though they have the mechanism for lower threshold of the SBD to dollar peg in place since its inception but the upper threshold was never introduced and once the upper threshold of the peg was broken they have been waiting for it to come back to the dollar price and if it does they might be introducing that upper threshold in place.

Whatever happens the purchase of SBD at one dollar is a n deal that essentially carries no loss. If the price goes up it's a win -win and price simply cannot go down. Even if it goes down we can always redeem the SBD token for one dollar of steem.
So it really is a good decision since there is essentially no downside of buying the SBD at this price.