The first thing that came to mind for me: how do you change a single site's password? The article doesn't say. It only mentions that changing the master password would require changing all passwords. That also seems like a complete non-starter.
There is an array of useful functionality that modern password managers provide, too: password sharing, saving select file content securely, password history, storage of security questions and answers, storing username (when you use something atypical for anonymity).
I can't help but feel like this idea is a dud. It's neat in an academic sense but it can't seriously compete with what already exists.