Julia Magas, writing on CoinTelegraph, is concerned about the security of data held in block chain style data structures.

We are hearing, with increasing and disturbing frequency, about cloud servers that have been left open to attack by malicious or accidental agents. Millions and billions of records are being stolen from computer systems that may be as strong as Fort Knox, but a simple misconfiguration can lead to information being leaked out. See here for another 49 million records exposed in an Amazon Elasticsearch database:

https://securityaffairs.co/wordpress/98733/breaking-news/straffic-data-leak.html

So is block chain more secure? Is it a better way to store our personal and private information?

It may be a usefully secure infrastructure for long term storage of material that benefits from its very specific characteristics, but secure does not necessarily mean that personal data is suitably secured.

Julia's article analyses many of these considerations. In my view “secure” does not necessarily mean appropriately secured.