I don't see any real problems with the proposed increase from 10% to 30%. IMO such a ratio isn't particularly dangerous.
It also doesn't really discourage me as far as the future prospect of HBD. HBD was designed from early on to be better than UST.
As far as utility goes, I had to collect USD payments from 8 people on Hive, and having HBD really made it nice and easy to do it.