I don't think liquidity plays any role here.
When you use the conversion tool from HIVE to HBD you create those HBD burning those HIVE (and viceversa in the other way), adding/removing tokens to/from circulation.
It's all about inflation and balance between marketcaps of the two system currencies this blockchain has.
HBD is being created and removed in a various way, but the conversions play the major role here in both directions. Other ways HBD is created is DHF proposal payouts, author rewards and interest.
Also this,
https://peakd.com/hive-13323/@dalz/rxdxls
And this,
https://peakd.com/hive-167922/@dalz/hive-inflation-for-may-2023-the-hive-supply-reaches-400m
Correct, but that would require Stable Coin -> HIVE -> HBD - which is fine by me, but some stakeholders may not understand these mechanisms and elect to vote not in favour of the proposal.
This is why I listed this as a risk.