[Edmond]

1.Backup and recovery with this solution is no different from backup and recovery of your phone. It is a potential issue but not unique. Cryptographic certificates and associated keys reside on your device.

2.The data format issue is (or was) indeed a concern though it was never insurmountable. A data dictionary would have been the most straight forward approach to address it: https://cipheredtrust.com/doc/#data-processing

I say data format discernment was a concern because as faith would have it, we now have the perfect tech to address that, LLMs. You can shove any data format into an LLM and it will spit out a transformation into what you are looking for without the need to know the source format.

Browsers are integrating LLM features as APIs so this type of use would be feasible both for front and back end tasks.