The answer is probably both, although maybe for different reasons.

CRYPTOCURRENCY

I've read a few times now that blockchain technology, at least as it currently exists, along with the current internet speeds worldwide, I would imagine, is not the most efficient way to log anything, let alone a cryptocurrency. What an open ledger allows for is decentralization, security, verification, etc. But there are ways to more efficiently and similarly secure cryptocurrency transactions without a blockchain.

We've yet to see what they will produce, but it will be interesting to see what Facebook and others do with the tokens they are supposedly creating. They won't really have a need for a decentralized token, not in the sense that STEEM and others are supposed to be.

BLOCKCHAINS

STEEM itself already proves that there isn't a need for a cryptocurrency to have a use case for blockchain technology, by the simple fact there are hundreds of thousands of posts and comments on a daily basis added to the blockchain. Yes, some of those get some form of rewards, but my guess is, the vast majority of comments go without any compensation.

There is no potential for any remuneration when someone resteems a post, either. So people do at least a few things without rewards, and in many cases, without expectation of it.

Blockchains are good for legal contracts, or the storage of data, particularly when it comes to validating ownership. Blockchains are best for censorship, even though comments or posts can be grayed out on a front end..

I'm sure as blockchain technology continues to progress, in conjunction with cryptocurrency, that the use cases for both will not only intertwine, but diverge. Hopefully, we're only seeing the tip of the iceberg of what either technology can do.