Lowering the HIVE value doesn't cause any more conversions.

It doesn't? If I understand it correctly HBD is backed by Hive, thus the name. So if the Hive value gets lower, then the stabilizer will be forced to convert, which is what is happening now.

But then again with less selling and more buying of HIVE we might not care at all because the HIVE price would be going up and not down.

But the opposite is happening right now. People are not buying, and a lot of accounts are converting/creating more Hive which makes things worse.