I hate to break it to you but the greater market does not care about centralized vs decentralized. They will go to whomever has the best utility and user experience.
It is right that people don't care as long as it works but:
There are two valuable attributes of blockchain technology:
a) Holding the private keys (you can do this with USD on Ripple (or am I wrong here?)) = funds can't be seized even with a centralized issuer except if they are seized for all (lack of collateral or state intervention).
b) No (direct) counterparty risk. This can not be done with ripple or any other system where a centralized issuer is backing the value of the token. And this is where the value of BitUSD comes from. Having a counterparty risk is highly costly: Any institution that holds funds for customers has high regulatory costs. Centralized solutions are therefore not per se cheaper for the customer.
I guess that customers would either trust a relatively young and unkown company that does audits (costly) and has a 100% reserve or big known banks that offer this service. The latter case it would likely be backed by a fractional reserve which is unlikely to be sustainable either individually (for a specific bank) or systemically.
So BitUSD has unique characteristics and will be very useful besides these centralized options.