The destruction of SBD (conversion) become avaiable below 1 usd exactly to avoid the hyperinflation, because It reduce the supply, increasing the value, and to help avoid that the sbd lose value
That is true if starting at $1. If you are starting at $10, then the currency can still hyperinflate and lose 90% of its value.
But the reason of SBD is exactly to be as close as 1 usd as possible, and when the price os above 1 dollar, the inflation increase exactly for the purpose of devaluate the SBD.
The hyperinflation would only occur if, when below 1 usd, the sbd would be printed at the same rate as now, on a continuous devaluation of the coin.
When below 1 usd, the mechanisms of deflation kicks in (less SBD printed, and the possibility to burn SBD through conversion)
We dont have hyperinflation right now, and we wont have hyperinflation when price os below 1 usd.
SBD Will never become Fully pegged to 1 usd, and like other strong currencies (usd, Eur, yen, and others) It doesnt have to be. But also It Will never rise in price nor lower in price forever because of the economic mechanism that already are in place on the system.
Also, allowing to convert SBD to steem now would burn SBD, thus increasing scarcity and driving the price up.