[8organicbits]

These all sound very cool, but they still sound like solutions in search of problems.

1 - Non-repudiation can be done with cryptographic signatures. Storing signed data doesn't require a blockchain. I think the major improvement is related to time-stamping, although there's lots of prior work there.

2 - When would someone ever need to prove this? If you can't prove the "what" or the "who", how is this useful?

3 - For Bitcoin, no, there's lots of tools to de-anonymize users. For others, I think that's true, but what's the use case beyond money laundering?