The characterization of SBDs really needs to be reassessed. They aren't pegged to the USD, that was just fanciful thinking when the steem blockchain was first conceived two years ago. The peg is unenforceable and in denial of free flowing supply/demand forces; the market has clearly demonstrated that over the past few months.

The Smart Media Tokens White Paper describes SBDs as an experimental asset and the increased demand for them and corresponding value ascension has likely been spurred by their correlation to SMT creation, as noted therein: "Initially smt_creation_fee will be set to 1 SBD & no means will be provided to update it."