Following this discussion i get the idea that the 'killer app' for monero would be a wallet where people see and use bitcoin, but in the background it gets converted to monero on a (decentralized of course) exchange.
Bitcoin and the public blockchain can and should be used by governments and other open organizations, while this monero wallet would be for privacy. also, the wallet would automatically 'mix' bitcoin if taken in/out a monero wallet on payment if it makes a new address every time