Yes, but HBD isn't needed in order for there to be a useable stablecoin.
The Internal Market only has one trading pair, HBD/HIVE. That isn't needed. There are already many ways of trading on a Dex or Swapping. Back then we didn't have that unless you did a centralized exchange.
I use Stablecoins all the time to the tune of tens of thousands per year, they are very useful.
There is currently no way to implement a truly decentralized exchange for HIVE apart from the internal market. Someone always has to custody the HIVE, which is centralized.
At some point maybe there will be a powerful enough smart contract system implemented on HIVE to make this possible, or maybe someone will figure out a clever method to do it another way, but for now, that's all we have.