I think with the 50% of HBD savings on Hive, it's a no loss. In case of any hack on Polygon (that is of it can ever happen with the cold wallet in place), it will be possible for everyone investing in pHBD to at least recover the wrapped HBD with 10% savings interest at least.
RE: pHBD is 1:1 Backed with HBD On the Hive Blockchain | Mechanics Deep Dive