In summary, using an HD Wallet to access a personal data store provides multiple benefits:
Data agnostic. Securely input, access and share any kind of file or record by providing keys and digital signatures.
Structured access. A way to organize authorized access to information into a structured hierarchy.
Authenticated data and proven identity without storing third party personal information.
Blockchain available, but not dependent. Information sharing transactions can be tied directly to a universal ledger as a public proof and/or as a financial transaction, but are not required to be. Wallets can be used solely as structured access to a data store, even though wallets are valid bitcoin addresses.
Encapsulation. Because each data element has a unique address, any one breach can be insulated from an attack on another.
Privacy. Without a high-level key, no one element of data can be tied to any other. With this level of data anonymity, more data can be donated by users for use in various forms of data commons.
A universal set of addresses. Using a public-private key hierarchy for data access provides for a universal address to read or write information based on an individual’s HD Wallet. A physician's office could send secure patient information to fulfill Meaningful Use requirements, for example.
Longitudinal tracking. All transactions are time-stamped, so all records can become a longitudinal record.
Security. Encryption of data by default.
Personal data as a service. Opens the door to have an API to share what you want with whom you want.