The same API part isn't surprising, content addressed stores are the most natural way to accept encrypted data.

The public storage networks are targeting a different use case than Blobcache though, which I think of as a private or web-of-trust storage network. To use a cryptocurrency backed storage solution, one must manage accounts, or a wallet of transaction outputs, connect to unknown parties on the internet, and pay for the increased redundancy. There's also legal risk, depending on the jurisdiction, when allowing untrusted parties to store arbitrary information on one's devices.

I don't want to consult the global economy in order to make use of my extra hard drives, which would otherwise be idle.