They are inseparable
Yes, I don't understand why people can say the currency function has a less bright future than the blockchain when all the security of the blockchain actually depends on the value of the currency, because it triggers the motivation to mine and secure the network.
Also note that OpenBazaar is putting all their long-term persistent data on the Bitcoin blockchain. All these various block chain apps can't make their own block chain, because they wouldn't have sufficient hashrate to protect from 51% attacks. It is much more likely that only one or just a few block chains will win and all these apps win run on them.
http://www.wired.com/2014/04/darkmarket
OpenBazaar is a cool idea, but so far the design is such that your store only stays up if you computer is always online. I think they need to put all the store items on a block chain. But I don't think they can do that using the Bitcoin block chain.
Yet another reason Bitcoin's block chain is not sufficient to do everything we need to do.