It's unclear to me how this project does anything to protect the identity of users or who is talking to whom. It's nice to know my messages can't be read, but if my ISP can see who I'm talking to and how often it's not doing much.
Also how to clients find one another? Tor and i2p sites are notoriously require friends or public wikis to share the addresses.
They have a platform and process for selling digital access to audiobooks and ebooks. Selling access to that type of content in an way that circumvents those DRM requirements is against their Terms of Service.