I think you did not get the point of IDENA or I did not get the point of your post. Idena does not use any personal data. It is not about storing identity on blockchain. It is new technology (different from POS and POW). You are doing Turing test (hard for AI easy for human) that proves that you are real human - not bot - that gives you permission to run a single node. This test is a guarantee that 1 real world person is equal to 1 node. This makes it possible to give each node equal voting power (not based by hash power or money locked). This makes it possible to implement sharding in easy and decentralized way.